{"id":1129,"date":"2025-04-20T20:59:39","date_gmt":"2025-04-21T00:59:39","guid":{"rendered":"https:\/\/teban54transit.com\/migrate\/?p=1129"},"modified":"2025-05-24T23:51:56","modified_gmt":"2025-05-25T03:51:56","slug":"idea-analysis-the-kendall-back-bay-subway-from-an-orange-line-re-route-to-the-pink-line","status":"publish","type":"post","link":"https:\/\/teban54transit.com\/?p=1129","title":{"rendered":"[Idea &amp; Analysis] The Kendall-Back Bay Subway: From an Orange Line Re-route to the &#8220;Pink Line&#8221;"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\" id=\"0-tldr\">TL;DR<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>People talk about reverse branching the Red Line via a new Mass Ave subway all the time. But if you shift the alignment further east, you now get another crazy idea: <span class=\"emph\"><strong>Reverse branching&#8230; the Orange Line?<\/strong><\/span><\/li>\n\n\n\n<li>Turns out, such a direct link between <strong><span class=\"emph\">Sullivan, Lechmere, Kendall and Copley\/Back Bay<\/span><\/strong> can be valuable in itself. I present two proposals that use it as a standalone route, the <span class=\"emph\"><strong>&#8220;Pink Line&#8221;<\/strong><\/span>.<\/li>\n\n\n\n<li>Personally, I favor this alignment over Mass Ave: <span class=\"emph\">it hits the high-demand destinations at more central locations than Mass Ave does.<\/span> Comparing the two alignments raises a question: <span class=\"emph\"><strong>How often are our imaginations limited by what exists today?<\/strong><\/span><\/li>\n\n\n\n<li>However, neither can replace a more conventional Urban Ring &#8212; which means such a subway proposal will likely remain too aggressive to be prioritized.<\/li>\n\n\n\n<li>Nevertheless, this allows for <span class=\"emph\">a closer look at <strong>the roles of Back Bay vs. Kendall<\/strong> in the network,<\/span> or even in the region as a whole. They have much more similarities than you might expect. Why is Back Bay often considered &#8220;extended downtown&#8221; nowadays, but not Kendall?<\/li>\n<\/ul>\n\n\n\n\n\n<h2 class=\"wp-block-heading\" id=\"1-background-the-mass-ave-red-line-proposal\">Background: The &#8220;Mass Ave Red Line&#8221; Proposal<\/h2>\n\n\n\n<p>You had probably seen this proposal before: <strong>Reverse branching the Red Line (RL) via Mass Ave.<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"3376\" height=\"3873\" src=\"https:\/\/teban54transit.com\/migrate\/migrate\/wp-content\/uploads\/2025\/04\/RL-Mass-Ave-min.png\" alt=\"\" class=\"wp-image-1128\" style=\"object-fit:cover\" srcset=\"https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/RL-Mass-Ave-min.png 3376w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/RL-Mass-Ave-min-262x300.png 262w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/RL-Mass-Ave-min-893x1024.png 893w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/RL-Mass-Ave-min-768x881.png 768w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/RL-Mass-Ave-min-1339x1536.png 1339w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/RL-Mass-Ave-min-1785x2048.png 1785w\" sizes=\"auto, (max-width: 3376px) 100vw, 3376px\" \/><figcaption class=\"wp-element-caption\">The Red Line reverse branching proposal, which has decent popularity among transit enthusiasts.<\/figcaption><\/figure>\n\n\n\n<p>The motivation is very natural and explains its popularity: Mass Ave, a major north-south <em>road<\/em> corridor in a region where north-south <em>rapid transit<\/em> connectivity is scarce, also happens to be on or close to the Red Line on both ends. So why not create an alternative route for Red Line trains to run under?<\/p>\n\n\n\n\n\n<p>This is an example of <strong><span class=\"emph\">reverse branching<\/span><\/strong>:<\/p>\n\n\n\n\n\n<ul class=\"wp-block-list\">\n<li>Typically, a rapid transit line runs in a single trunk in the &#8220;downtown&#8221; area where demand is at its highest and may sometimes diverge into multiple branches in the &#8220;outer neighborhoods&#8221; where demand is lower.<\/li>\n\n\n\n<li>But the proposal above creates two <em>reverse<\/em> branches <em>within<\/em> &#8220;downtown&#8221;, one via Park St and one via Mass Ave. Each branch&#8217;s frequency is half of that of the common northside terminus, Alewife.<\/li>\n<\/ul>\n\n\n\n\n\n<p>To be clear: <span class=\"emph\">Reverse branching is often a bad idea.<\/span> <a href=\"https:\/\/railsroadsriverside.com\/branches-are-not-your-friend\/\">RailsRoadsRiverside<\/a> and <a href=\"https:\/\/pedestrianobservations.com\/2018\/06\/15\/reverse-branching-does-not-save-you-the-transfer\/\">Alon Levy<\/a> have written about this in depth. Thus, <span class=\"emph\"><strong>I am NOT in favor of the Mass Ave Red Line proposal myself,<\/strong><\/span> both due to reverse branching and for many other reasons <span class=\"note\">(detailed later)<\/span>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"2-reverse-branching-for-funsies-the-orange-line\">Reverse Branching for Funsies: The Orange Line<\/h2>\n\n\n\n<p>But if we want to have some fun and play around with reverse branching anyway&#8230; Why stop at the Red Line?<\/p>\n\n\n\n<p>Entering an even crazier proposal: <strong>Reverse branching the Orange Line (OL), via&#8230; Lechmere and Kendall!<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/teban54transit.com\/migrate\/migrate\/wp-content\/uploads\/2025\/04\/OL-Kendall-min-1024x1024.png\" alt=\"\" class=\"wp-image-1125\" srcset=\"https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/OL-Kendall-min-1024x1024.png 1024w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/OL-Kendall-min-300x300.png 300w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/OL-Kendall-min-150x150.png 150w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/OL-Kendall-min-768x768.png 768w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/OL-Kendall-min-1536x1536.png 1536w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/OL-Kendall-min-2048x2048.png 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">My Orange Line reverse branching idea. <strong>[NOT A SERIOUS PROPOSAL]<\/strong><\/figcaption><\/figure>\n\n\n\n<p><span class=\"emph\"><strong><em>Disclaimer: This is NOT a serious proposal.<\/em><\/strong> While some aspects of it are worth considering, I am NOT proposing to reverse branch the Orange Line exactly as such.<\/span><\/p>\n\n\n\n<p>This idea is probably much less trivial than the Mass Ave one. But here&#8217;s the <em>unserious, almost childish<\/em> motivation:<\/p>\n\n\n\n<p>The Orange Line makes a big C-shaped detour in downtown Boston between Sullivan Square and Back Bay, and it&#8217;s even more roundabout than the Red Line. What if we cut it straight?<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"3-the-sullivan-lechmere-kendall-back-bay-subway\">The Sullivan &#8211; Lechmere &#8211; Kendall &#8211; Back Bay Subway<\/h2>\n\n\n\n<p>Once we look <em>between<\/em> <strong><span class=\"emph\">Sullivan Sq<\/span><\/strong> and <strong><span class=\"emph\">Back Bay<\/span><\/strong>, we see a few very, very interesting nodes&#8230; <strong><span class=\"emph\">Lechmere<\/span><\/strong> and <strong><span class=\"emph\">Kendall<\/span><\/strong>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"4-geographical-alignment\">Geographical Alignment<\/h3>\n\n\n\n\n\n<p>Despite the lack of an underlying road network <span class=\"note\">(unlike Mass Ave)<\/span>, <span class=\"emph\">these nodes are much better aligned north-to-south than you might expect:<\/span><\/p>\n\n\n\n\n\n<ul class=\"wp-block-list\">\n<li>Lechmere is almost due south of Sullivan. <span class=\"note\">If you want, there&#8217;s even a rail right-of-way (ROW), the Grand Junction, that continues due south past Sullivan for longer than OL itself does.<\/span><\/li>\n\n\n\n<li>Third St, the main north-south road corridor through Kendall Sq, ends just two blocks away from Lechmere&#8217;s station entrance <span class=\"note\">(and one block from the bus loop)<\/span>.<\/li>\n\n\n\n<li>Dartmouth St is one of the most prominent north-south roads through Back Bay, passing through Copley Square and both Green and Orange Lines&#8217; stations. If you extrapolate Dartmouth St further north across Charles River&#8230; You end up in Kendall, <em>almost<\/em> dead on at the Red Line station and Third St!<\/li>\n<\/ul>\n\n\n\n<p>So, if you want to be God and ignore construction costs&#8230; Why not build a tunnel straight through all this?<\/p>\n\n\n\n<p>In fact, most of my map above follows existing roads, and where it doesn&#8217;t, it was mostly crossing either the Charles or rail yards. The only exception is going from First St to Third St in East Cambridge.<\/p>\n\n\n\n\n\n<h3 class=\"wp-block-heading\" id=\"5-strong-local-demands\">Strong Local Demands<\/h3>\n\n\n\n<p>Not only are these nodes nicely aligned, but <span class=\"emph\">they all have great prominence themselves:<\/span><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong><span class=\"emph\">Sullivan Square<\/span><\/strong> is the first major <span class=\"emph\">transfer hub<\/span> north of downtown Boston. Today, 11 bus routes bring residents from Somerville, Charlestown, Everett, Chelsea and more places to connect to the Orange Line.<\/li>\n\n\n\n<li><strong><span class=\"emph\">Lechmere<\/span><\/strong> is not only the diverging point of both branches of <span class=\"emph\">Green Line Extension (GLX)<\/span>, but the area has also seen plenty of <span class=\"emph\">recent development<\/span>. <a href=\"https:\/\/cambridgecrossing.com\/\" data-type=\"link\" data-id=\"https:\/\/cambridgecrossing.com\/\">Cambridge Crossing<\/a> is now home to many high-rise apartments and corporate offices.<\/li>\n\n\n\n<li><strong><span class=\"emph\">Kendall Square<\/span><\/strong> is arguably <span class=\"emph\">the biggest employment center outside of downtown Boston<\/span>, with around 70,000 jobs between tech, MIT and more. It hosts more jobs than Central Sq and Harvard Sq <em>combined<\/em>. The Red Line sees significant &#8220;reverse commute&#8221; demand from downtown Boston into Cambridge during AM peak, with a large amount attributed to Kendall.<\/li>\n\n\n\n<li><strong><span class=\"emph\">Back Bay<\/span><\/strong> (including <strong>Copley<\/strong> Square) is what I would consider Boston&#8217;s <span class=\"emph\">&#8220;extended downtown&#8221;<\/span>, if not part of the downtown itself. Besides its own 70,000 or so jobs (similar to Kendall), it&#8217;s also a vibrant center for shopping, dining, conferences and more.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"6-circumferential-connections\">Circumferential Connections<\/h3>\n\n\n\n\n\n<p>In addition to bringing people to destinations along the line, such a hypothetical subway can also play a crucial role in the network: <span class=\"emph\">connecting (almost) all other lines, and doing so <em>outside<\/em> the downtown core.<\/span><\/p>\n\n\n\n\n\n<p>Boston&#8217;s rapid transit network is almost entirely hub-and-spoke in nature, with lines meeting in the downtown core <span class=\"note\">(Shawmut Peninsula)<\/span> and radiating outwards. This is often not ideal for people traveling between neighborhoods, or <span class=\"note\">(arguably more often)<\/span> to employment centers away from the core. <\/p>\n\n\n\n<p>Central Square (Cambridge) is 1.7 miles from Copley Square as the crow flies, but the Red and Green lines carry you through 3.3 miles &#8212; almost twice as long!<\/p>\n\n\n\n<p>This is why most of the world&#8217;s largest rapid transit systems typically have either a ring route or overlapping services forming a ring. Even in Boston, the idea of an <a href=\"https:\/\/en.wikipedia.org\/wiki\/Urban_Ring_Project\">&#8220;Urban Ring&#8221;<\/a> has been touted around forever, and even went through official studies in the 2000s.<\/p>\n\n\n\n\n\n<p>While this Kendall-Back Bay proposal doesn&#8217;t look quite like a conventional Urban Ring, it achieves several similar objectives. More comparisons will be made in <a href=\"#11-kendall-bby-vs-urban-ring\">later sections<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"7-towards-a-standalone-line-the-pink-line\">Towards a Standalone line: The Pink Line<\/h2>\n\n\n\n<p>Even without seriously advocating for reverse branching either RL or OL &#8212; which I don&#8217;t &#8212; we can nevertheless still use the core alignment of the <strong><span class=\"emph\">Sullivan &#8211; Lechmere &#8211; Kendall &#8211; Back Bay subway<\/span><\/strong> to get <em>slightly<\/em> more sensible ideas.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"8-the-red-orange-marriage-a-crazier-red-x\">The Red-Orange Marriage: A Crazier &#8220;Red X&#8221;<\/h3>\n\n\n\n<p>I&#8217;ll first start with a proposal that&#8217;s <em>still in the &#8220;insane&#8221; category<\/em>, but less so than reverse branching.<\/p>\n\n\n\n<p>Let&#8217;s think of the more standard (non-reverse) <strong>branching<\/strong>, where a line splits outside of downtown towards different neighborhoods. Two such cases are relevant here:<\/p>\n\n\n\n\n\n<p>The Red Line has two branches to the south. This has always <a href=\"https:\/\/railsroadsriverside.com\/inevitabilities-in-life-death-taxes-and-decreased-frequencies-on-branches\/\">limited the frequencies<\/a> that each of Ashmont and Braintree can receive, especially in recent years when slow zones and shortages plagued the branches with <a href=\"https:\/\/www.reddit.com\/r\/mbta\/comments\/15e6pls\/red_line_headway\/\">20+ min headways<\/a>. Even though the <a href=\"https:\/\/www.mbta.com\/projects\/red-line-program\">Red Line Transformation<\/a> project will eventually improve branch headways to <a href=\"https:\/\/web.archive.org\/web\/20181010185351\/http:\/\/blog.mass.gov\/transportation\/mbta\/mbta-awards-signal-upgrade-contract-for-red-and-orange-lines\/\">6 minutes<\/a>, it will always be twice as long as that of the main Red Line trunk: every 3 minutes.<\/p>\n\n\n\n<p>There have been various fantasy proposals to &#8220;save&#8221; the Red Line branches, by diverting one of them into a new right-of-way (ROW) north of JFK\/UMass. This idea is often called the <strong><span class=\"emph\">&#8220;Red X&#8221;<\/span><\/strong>: Turning the line from a \u03bb shape into two independent X-shaped lines, such that <em>each<\/em> of them can run every 3 minutes.<\/p>\n\n\n\n<p>Most mainstream Red X proposals usually have the new trunk head to downtown Boston. This includes the <a href=\"https:\/\/archboston.com\/community\/threads\/crazy-transit-pitches.3664\/page-204#post-382676\"><strong>textbook Red X<\/strong><\/a> by F-Line to Dudley, which essentially builds a <strong>Congress St Subway<\/strong> from South Station to North Station.<\/p>\n\n\n\n\n\n<p>While the Orange Line doesn&#8217;t have any branches today, there have nevertheless been <em>countless<\/em> ideas for a new OL branch among transit enthusiasts and even real-world advocacy groups.<\/p>\n\n\n\n<p>The most popular idea is an <strong><span class=\"emph\">Orange Line branch to Everett<\/span><\/strong>. North of Sullivan Square, the branch would diverge onto the Eastern Route (the Newburyport\/Rockport Line&#8217;s ROW) to Sweetser Circle, from which it either heads north under Everett&#8217;s Broadway or continues east to Chelsea.<\/p>\n\n\n\n<p>I myself have never been fond of branching the Orange Line as a <em>long-term<\/em> measure, and the primary reason is, again, <span class=\"emph\">frequency<\/span>. <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The ongoing <a href=\"https:\/\/www.mbta.com\/projects\/orange-line-program\">Orange Line Transformation<\/a> project will upgrade both its signals and rolling stock to support a frequency of &#8220;only&#8221; 4.5 minutes. Creating branches without any other signaling upgrades would result in <strong>9-minute<\/strong> frequencies for Malden, which I feel is unacceptable given its status as a dense suburb and bus transfer hub.<\/li>\n\n\n\n<li>The <a href=\"https:\/\/www.mapc.org\/wp-content\/uploads\/2019\/03\/SPRING19_LowerMysticReport_FULL.pdf#page=90\">Lower Mystic Regional Working Group report<\/a> included an Orange Line branch as Alternative 8. It also advocated for <a href=\"https:\/\/www.mapc.org\/wp-content\/uploads\/2019\/03\/SPRING19_LowerMysticReport_FULL.pdf#page=30\">improving OL&#8217;s frequencies to every 3 minutes<\/a>, which requires &#8220;an additional 78 cars [&#8230;], a new signal system, upgrades in power supply, and an expanded maintenance facility.&#8221; Even with such investments, a Malden branch would still only see trains every <strong>6 minutes,<\/strong> a downgrade from 4.5 minutes.<\/li>\n\n\n\n<li>Not to mention, all of this assume rush-hour headways. Frequencies during <strong>off-peak<\/strong> hours and especially on <strong>weekends<\/strong> would likely become intolerable on each branch, as anyone from Dorchester and Quincy can tell you.<\/li>\n<\/ul>\n\n\n\n<p>However, a new rapid transit line that does <em>not<\/em> merge with the Orange Line seems perfectly reasonable, if not necessary. So&#8230;<\/p>\n\n\n\n\n\n<p>If there&#8217;s an existing Red Line branch to the south, and a frequently touted Orange Line &#8220;branch&#8221; to the north&#8230; <strong><span class=\"emph\">Why not join the two branches with a new trunk through downtown?<\/span><\/strong> So far, this is still within the realm of reality for standard Red X proposals <span class=\"note\">(if not the most common belief of what the Red X should do)<\/span>.<\/p>\n\n\n\n<p>But here&#8217;s where the &#8220;crazy &#8220;insane&#8221; part comes in: Instead of going through the downtown core, <strong><span class=\"emph\">why not connect them via the Kendall-Back Bay subway?<\/span><\/strong><\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"6496\" height=\"12992\" src=\"https:\/\/teban54transit.com\/migrate\/migrate\/wp-content\/uploads\/2025\/04\/Pink-Quincy-min.png\" alt=\"\" class=\"wp-image-1127\" srcset=\"https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/Pink-Quincy-min.png 6496w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/Pink-Quincy-min-150x300.png 150w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/Pink-Quincy-min-512x1024.png 512w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/Pink-Quincy-min-768x1536.png 768w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/Pink-Quincy-min-1024x2048.png 1024w\" sizes=\"auto, (max-width: 6496px) 100vw, 6496px\" \/><figcaption class=\"wp-element-caption\">My idea of the Pink Line from Everett to Braintree, via the Kendall-Back Bay subway, Roxbury, and taking over the RL Braintree Branch. <strong>[NOT A SERIOUS PROPOSAL]<\/strong><\/figcaption><\/figure>\n\n\n\n<p><span class=\"emph\"><strong><em>Disclaimer: This is NOT a serious proposal.<\/em><\/strong> While some aspects of it are worth considering, I am NOT proposing to reroute the Braintree Branch exactly as such.<\/span><\/p>\n\n\n\n\n\n<p>The reason why this is not serious should be obvious: <strong><span class=\"emph\">It&#8217;s too much of a detour for Quincy and Braintree, <em>particularly<\/em> for those seeking downtown.<\/span><\/strong><\/p>\n\n\n\n\n\n<ul class=\"wp-block-list\">\n<li>Most riders probably want to head to the downtown core. Even though Copley can be seen as the &#8220;extended downtown&#8221;, I doubt it has the same draw.<\/li>\n\n\n\n<li>Riders seeking the original Red Line will have a <strong>forced transfer at Fields Corner<\/strong>. I haven&#8217;t found any way to make the transfer seamless: it will probably be a tedious elevated-to-underground transfer no matter what. <span class=\"note\">In contrast, more traditional Red X proposals often allow cross-platform transfers at JFK\/UMass with track modifications.<\/span><\/li>\n<\/ul>\n\n\n\n<p>(Somewhat surprisingly, distance and &#8220;roundaboutness&#8221; aren&#8217;t actually the main issue. Today&#8217;s Red Line spans <strong>7.86 miles<\/strong> between Kendall and North Quincy, whereas my Pink Line takes&#8230; <strong>7.95 miles<\/strong>. Longer, but not by much.)<\/p>\n\n\n\n\n\n<p>Having said that, there are many valuable and\/or fun aspects to consider out of this (otherwise insane) proposal:<\/p>\n\n\n\n\n\n\n\n<p>First of all, <span class=\"emph\">I believe that <em>both<\/em> <strong>Everett<\/strong> and <strong>Chelsea<\/strong> should get radial transit lines<\/span> (in an ideal world), and they present the strongest arguments for new lines to the north of metro Boston.<\/p>\n\n\n\n\n\n<p>My <a href=\"https:\/\/teban54transit.com\/migrate\/?p=862\">population density map<\/a> shows this entire quadrant, between the Orange and Blue lines, as one of the densest among transit deserts. Their densities appear close to Somerville and Cambridge. Yet, they don&#8217;t even have a radial mainline rail ROW; the Eastern Route skirts through the parts of Everett where people actually live. Disregarding cost, a radial route through Everett&#8217;s Broadway is the obvious choice for a new rapid transit line.<\/p>\n\n\n\n\n\n<p>The more interesting question is: Why did I send my Pink Line into Everett, <em>instead of<\/em> to Chelsea and\/or covering them both?<\/p>\n\n\n\n\n\n<p><strong>TL;DR:<\/strong> In this idealized, cost-blind world, I believe that <span class=\"emph\"><strong>Chelsea<\/strong> is best served by its own dedicated rapid transit line<\/span> &#8212; which has stronger arguments for <span class=\"emph\">direct service to the downtown core<\/span> than Everett does.<\/p>\n\n\n\n\n\n<ul class=\"wp-block-list\">\n<li>Besides the Orange Line ROW, Chelsea has a more direct option: the <strong>Tobin Bridge<\/strong>. With its <a href=\"https:\/\/www.mass.gov\/maurice-j-tobin-bridge-long-term-strategic-planning-study\">replacement<\/a> in planning, the idea and even advocacy efforts of bringing rail to Tobin is very real and should be prioritized. A Chelsea-Everett-Sullivan-downtown &#8220;wraparound&#8221; service is much less attractive.<\/li>\n\n\n\n<li>The Lechmere-Kendall-BBY subway has better <strong>geographic synergy<\/strong> for Everett than Chelsea. Connecting it to Tobin Bridge would require the Pink Line to turn east to Community College rather than north to Sullivan. For Chelsea residents, the OL transfer point being at Community College is more &#8220;out of the way&#8221; than something like North Station.<\/li>\n\n\n\n<li>Chelsea already has a direct bus connection to downtown <span class=\"note\">(Shawmut Peninsula)<\/span>: the 111. Everett currently doesn&#8217;t, and any such trips from Everett require a transfer at Sullivan. Thus, Everett residents may be more open to an Orange Line transfer than Chelsea residents.<\/li>\n<\/ul>\n\n\n\n\n\n<p>One problem with &#8220;Pink Line Everett-Copley, another line Chelsea-downtown&#8221; is that <em>these two lines themselves don&#8217;t intersect<\/em>. I don&#8217;t think that&#8217;s a big problem, especially if layered with buses filling the circumferential gaps between the two cities.<\/p>\n\n\n\n\n\n<p><strong>South End<\/strong> is another one of those <a href=\"https:\/\/teban54transit.com\/migrate\/?p=862\">extremely dense<\/a> neighborhoods that existing transit lines avoid; in fact, it may just be the densest and the most populous. Most people agree that the Silver Line today doesn&#8217;t do it justice.<\/p>\n\n\n\n<p>To be clear, I think <span class=\"emph\">a radial, <strong>&#8220;local&#8221;-ish<\/strong> service on Washington St towards Downtown Crossing is still needed no matter what.<\/span> This is typically assumed to be a Washington St streetcar in most <a href=\"https:\/\/teban54transit.com\/migrate\/?p=58\">proposals<\/a>, and usually has closely spaced stops.<\/p>\n\n\n\n<p>Nevertheless, I used the Pink Line proposal as a fun opportunity to <span class=\"emph\">explore grade-separated, <strong>&#8220;metro&#8221;-ish<\/strong> service to South End with longer stop spacing,<\/span> <em>in addition to<\/em> local service. It&#8217;s a very natural instinct: The north-south route through Back Bay basically points <em>right at<\/em> South End, begging to be extended beyond the Orange Line.<\/p>\n\n\n\n<p><strong>Note:<\/strong> I could (and probably should) have let the Pink Line run via Harrison Ave rather than Washington St, for more direct access to Boston Medical Center. But that&#8217;s a more minor point.<\/p>\n\n\n\n\n\n<p>Just like with South End, most people believe that current transit solutions to <strong>Nubian<\/strong> are far from enough. Personally, I even think that a single Washington St streetcar won&#8217;t be enough for Nubian (unlike for South End).<\/p>\n\n\n\n<p>My <a href=\"https:\/\/teban54transit.com\/migrate\/?p=58\">past attempts <span class=\"note\">(the G train in my GLR map)<\/span><\/a> at bringing &#8220;metro&#8221; service to Nubian were typically in the form of <strong><span class=\"emph\">&#8220;light metro&#8221;<\/span><\/strong>: a grade-separated route feeding into the Green Line&#8217;s Tremont St subway, with light rail vehicles. It&#8217;s the &#8220;Nubian Express&#8221; compared to Washington St&#8217;s &#8220;Nubian Local&#8221;, and is <a href=\"https:\/\/railsroadsriverside.com\/f-line-to-nubian-isnt-enough-a-speed-and-travel-time-analysis-of-different-transit-modes\/\">the only way to fulfill the &#8220;equal or better&#8221; promise<\/a>.<\/p>\n\n\n\n<p>While I ultimately still believe that &#8220;light metro&#8221; is likely the right choice for Nubian, this post offers us another consideration: <span class=\"emph\">How about a new, full-blown heavy rail line?<\/span><\/p>\n\n\n\n<p>To be clear, this is <em>not<\/em> suggesting that the Pink Line&#8217;s <strong>alignment <\/strong>&#8212; sending Nubian trains to Back Bay &#8212; is the most ideal. One of the primary reasons why I still favor the &#8220;light metro&#8221; approach is alignment: by plugging into the <span class=\"note\">(abandoned but intact)<\/span> Pleasant St portal near Bay Village, it easily strikes a balance between cost and desirability. <\/p>\n\n\n\n<p>But &#8220;greenfield alignment&#8221; is still an interesting thought exercise regardless, with a range of options beyond just Back Bay vs. Bay Village (which are better saved for another post).<\/p>\n\n\n\n\n\n<p>The parts of <strong>Roxbury further south of Nubian<\/strong> is often ignored in such discussions. True, Nubian is the main hub of Roxbury, but that doesn&#8217;t mean all needs stop there.<\/p>\n\n\n\n<p>In particular, <strong>Warren St<\/strong> between Nubian and at least Grove Hall <span class=\"note\">(if not to Franklin Park and\/or all the way to Mattapan)<\/span> is an important, well-established transit corridor:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>It&#8217;s the main spine across Roxbury&#8217;s municipal boundaries. <\/li>\n\n\n\n<li>Today, it&#8217;s served by <em>two<\/em> Frequent Bus Routes that both rank extremely highly in ridership systemwide. <\/li>\n\n\n\n<li>Even for other bus routes <span class=\"note\">(14, 19)<\/span>, people explicitly <em>asked<\/em> for service to be retained on Warren St when the Bus Network Redesign initially attempted to move them to nearby streets.<\/li>\n<\/ul>\n\n\n\n<p>An often-overlooked point is that <span class=\"emph\">Fairmount Line improvements do NOT eliminate Roxbury&#8217;s and Warren St&#8217;s needs.<\/span> Fairmount Line essentially avoids Roxbury by tracking its boundary with Dorchester, just like the Orange Line does to the west. Warren St is further from the Fairmount Line than Jamaica Plain is from the Orange Line, yet calls for improving service on Bus Route 39&#8217;s corridor never stopped.<\/p>\n\n\n\n<p>In <a href=\"https:\/\/archboston.com\/community\/threads\/crazy-transit-pitches.3664\/page-286#post-467695\">more recent brainstorming proposals<\/a>, I (and others) have experimented with extending one of the Nubian LRT lines down to MLK Blvd or Grove Hall, though typically not all the way to Mattapan. But as the Pink Line shows here, you can certainly let a true HRT line do it (in theory), and it also avoids the southern half of Warren St being too narrow for dedicated surface lanes.<\/p>\n\n\n\n\n\n\n\n<p>First, an opinion: <span class=\"emph\">Once south of Franklin Park&#8217;s entrance, a new <em>grade-separated rapid transit<\/em> route that continues down Blue Hill Ave stops making sense<\/span> &#8212; now that proximity to the Fairmount Line is actually true and relevant.<\/p>\n\n\n\n\n\n<p>South of Franklin Park, Blue Hill Ave and the Fairmount Line ROW converge towards Mattapan, with most points within a 10-min walk. Blue Hill Ave&#8217;s walkshed also becomes obstructed by Franklin Park.<\/p>\n\n\n\n<p><em>Surface<\/em> transit (BRT or streetcar LRT) on Blue Hill Ave definitely makes sense, due to its ample width, the successful Bus Route 28 already existing, and <a href=\"https:\/\/www.mbta.com\/projects\/blue-hill-avenue-transportation-action-plan\">ongoing efforts for center-running bus lanes<\/a>. But I&#8217;m skeptical of the value of another grade-separated route here.<\/p>\n\n\n\n\n\n<p>You can terminate the Nubian-Warren line at Grove Hall or Franklin Park, of course. But my Pink Line proposal explores another possibility: <span class=\"emph\">How about creating a <em>circumferential<\/em> connection here?<\/span><\/p>\n\n\n\n<p>The Pink Line hops from Grove Hall to a Neponset infill, essentially <span class=\"emph\">intersecting 4 radial branches<\/span> <span class=\"note\">(Nubian-Warren, Fairmount, Ashmont, Braintree)<\/span>, even though it&#8217;s then absorbed into two of them.<\/p>\n\n\n\n<p>This is probably not the best way to do it (details below), but still a fun exercise!<\/p>\n\n\n\n\n\n<p>Not all transit lines are purely radial or purely circumferential. On a very broad level, here are two ways of mixing these two types, and my own nicknames for them. Links are to posts that Alon Levy has written on this topic.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong><a href=\"https:\/\/pedestrianobservations.com\/2014\/12\/31\/mixing-circumferential-and-radial-transit\/\">&#8220;Tangential lines&#8221;<\/a><\/strong>: Circumferential near the city center, radial in the outer neighborhoods.\n<ul class=\"wp-block-list\">\n<li><span class=\"note\">My Pink Line is, in some sense, already an example of this &#8212; largely depending on how &#8220;central&#8221; you think Kendall and Back Bay are.<\/span><\/li>\n\n\n\n<li><span class=\"note\">A more clear-cut example would be: Imagine if the Pink Line didn&#8217;t go through Kendall and Back Bay, but through Harvard and Allston.<\/span><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/pedestrianobservations.com\/2016\/08\/02\/mixing-circumferential-and-radial-transit-in-the-other-direction\/\">&#8220;L-hook lines&#8221;<\/a><\/strong>: Radial in the city center, circumferential in the outer neighborhoods.<\/li>\n<\/ul>\n\n\n\n<p>Alon Levy views L-hook lines more favorably than tangential lines, if the conditions are right.<\/p>\n\n\n\n<p>I had previously expressed my own thoughts on them <a href=\"http:\/\/archboston.com\/community\/threads\/transit-planning-h-tposting-ideas-so-bad-theyre-good.6999\/post-472596\">here<\/a>.<\/p>\n\n\n\n\n\n<p>Since the Nubian-Warren line has &#8220;nowhere&#8221; to go after Franklin Park, a crosstown turn definitely makes sense. But two factors argue against it:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><span class=\"emph\">Is the crosstown demand around Dorchester enough to warrant rapid transit?<\/span> My guess would be no: while the 22 and 23 buses are all busy and have some crosstown characteristics, it seems that demands here can be easily handled by buses.<\/li>\n\n\n\n<li><span class=\"emph\">Does the crosstown demand extend further to the west?<\/span> This is quite plausibly true, as you can continue along Seavers St and Columbus Ave to Jackson Square (OL), or even to the Green Line E branch and LMA. A dedicated crosstown route with more coverage may be better than an incomplete hook.<\/li>\n<\/ol>\n\n\n\n\n\n\n\n<h3 class=\"wp-block-heading\" id=\"9-down-to-earth-or-down-to-city-point\">Down to Earth, or Down to City Point<\/h3>\n\n\n\n<p>One final proposal, that&#8217;s also <strong>the most realistic<\/strong> (though still expensive):<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"4724\" height=\"6298\" src=\"https:\/\/teban54transit.com\/migrate\/migrate\/wp-content\/uploads\/2025\/04\/Pink-City-Point-min.png\" alt=\"\" class=\"wp-image-1126\" srcset=\"https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/Pink-City-Point-min.png 4724w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/Pink-City-Point-min-225x300.png 225w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/Pink-City-Point-min-768x1024.png 768w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/Pink-City-Point-min-1152x1536.png 1152w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/Pink-City-Point-min-1536x2048.png 1536w\" sizes=\"auto, (max-width: 4724px) 100vw, 4724px\" \/><figcaption class=\"wp-element-caption\">A more realistic Pink Line proposal from Everett to City Point, via the Kendall-Back Bay subway and South End.<\/figcaption><\/figure>\n\n\n\n<p>For the first time in this post, <span class=\"emph\">I&#8217;m actually comfortable with suggesting this as a concrete, &#8220;halfway-realistic&#8221; proposal.<\/span> This is not to say that it will happen: the &#8220;revised&#8221; Pink Line will still be expensive <a href=\"#14-cost\">(see below)<\/a>. In fact, <span class=\"emph\">it&#8217;s still well above the &#8220;budget&#8221; that I&#8217;m usually comfortable with.<\/span><\/p>\n\n\n\n<p>But back to the proposal itself. The main change from the &#8220;crazy Pink Line&#8221; is <span class=\"emph\">freeing it from responsibilities that are <em>not the most well-suited<\/em> for the Kendall-Back Bay subway:<\/span> namely, both the &#8220;Red X&#8221; <span class=\"note\">(absorbing one of its branches)<\/span> and the Nubian-Warren line.<\/p>\n\n\n\n<p>Instead, this now allows the Pink Line to head to another neighborhood that&#8217;s hungry for its own rapid transit: <strong><span class=\"emph\">South Boston<\/span><\/strong> <span class=\"note\">(Southie)<\/span>.<\/p>\n\n\n\n\n\n<p>As a recurring theme in this post&#8230; South Boston is yet another neighborhood that qualifies for better transit, in theory. Its <a href=\"https:\/\/teban54transit.com\/migrate\/?p=862\">density<\/a> is quite comparable to Cambridge, only outshined by the absolute densest neighborhoods in the entire region.<\/p>\n\n\n\n<p>While Southie is technically served by two <strong>Red Line<\/strong> stations, they&#8217;re at the literal corners of the neighborhood, with up to 3\/4 of their walksheds blocked by highways and rail yards. <\/p>\n\n\n\n<p>Most Southie residents need to transfer to <strong>buses<\/strong>, which have surprisingly strong demand: Routes 7 and 9 are among the most frequent and most heavily used bus routes that are not designated Key Bus Routes, which is even more impressive given their bad midday and weekend headways. Both are expected to become Frequent Bus Routes under the Bus Network Redesign.<\/p>\n\n\n\n\n\n<p>However, this may be a case where &#8220;does place X need heavy rail&#8221; goes beyond just the demographical statistics alone.<\/p>\n\n\n\n<p>I argue that a few unique factors are at play, which <em><strong>may<\/strong><\/em> change the calculus:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>South Boston&#8217;s employment patterns are&nbsp;<span class=\"emph\"><em>very <\/em><\/span><strong><span class=\"emph\">downtown-centric,<\/span><\/strong> especially Financial District-centric. It may be one of the most downtown-centric neighborhoods in metro Boston. A direct, shorter ride to downtown may be preferable over a transfer, especially an &#8220;out of the way&#8221; one.<\/li>\n\n\n\n<li>South Boston is much <span class=\"emph\">closer to downtown Boston<\/span> than most other neighborhoods. Thus, time savings from achieving higher speed <em>between<\/em> the neighborhood and downtown become less impactful.<\/li>\n\n\n\n<li>Since it&#8217;s somewhat geographically isolated, South Boston is primarily <span class=\"emph\">a destination, not a transfer hub<\/span>&nbsp;<em>(unlike Harvard, Nubian, Sullivan etc)<\/em>. There&#8217;s less of a need to carry &#8220;suburban&#8221; riders from further away into downtown quickly.<\/li>\n\n\n\n<li><span class=\"emph\">West Broadway<\/span> seems busier than Dorchester St with more commercial activities. Meanwhile, anything from Seaport (Summer St or L St) misses out on a huge chunk of South Boston&#8217;s population.<\/li>\n<\/ul>\n\n\n\n<p>These factors may have the following implications:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A route through <strong><span class=\"emph\">W Broadway &#8211; E Broadway<\/span><\/strong>, transferring to the Red Line at Broadway station, may be the most preferred alignment. It has the best coverage <span class=\"note\">(unlike Seaport-South Station)<\/span> while also being in the &#8220;right&#8221; direction towards downtown Boston <span class=\"note\">(unlike Andrew)<\/span>.<\/li>\n\n\n\n<li>Compared to a fast service that makes fewer stops and requires more walking, it&#8217;s plausible that that residents&nbsp;<em>may<\/em>&nbsp;prefer a <span class=\"emph\">&#8220;local&#8221;<\/span> service with more stops closer to home.<\/li>\n\n\n\n<li>Anything that&#8217;s more expensive than bus improvements should probably offer a <span class=\"emph\">one-seat ride<\/span> to (some parts of) downtown.<\/li>\n<\/ul>\n\n\n\n<p>This already implies that <span class=\"emph\">the Pink Line may not actually be the most ideal solution for South Boston.<\/span> It doesn&#8217;t go to the more &#8220;conventional&#8221; downtown, only to Back Bay. The number of stops it can make will likely be limited, if built as heavy rail.<\/p>\n\n\n\n<p>That said, my intention of routing the Pink Line as such was merely to explore the options, not to claim decisively that it&#8217;s the best.<\/p>\n\n\n\n\n\n<h2 class=\"wp-block-heading\" id=\"10-comparing-kendall-back-bay-to-other-alignments\">Comparing Kendall-Back Bay to Other Alignments<\/h2>\n\n\n\n<p>For the rest of this article, forget about the exact northern and southern alignments of the Kendall-Back Bay subway, beyond Sullivan and South End. Let&#8217;s instead compare it to other parallel rail corridors.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"11-kendall-bby-vs-mass-ave\">Kendall-BBY vs. Mass Ave<\/h3>\n\n\n\n<p>Here&#8217;s my opinion: <span class=\"emph\">The Sullivan-Kendall-Back Bay hits places that are <strong>more centrally located<\/strong>, and with <strong>higher demand<\/strong>, than the Mass Ave alignment.<\/span><\/p>\n\n\n\n\n\n<p>Here&#8217;s an employment density map that I have been working on (not yet finalized):<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1501\" height=\"1501\" src=\"https:\/\/teban54transit.com\/migrate\/migrate\/wp-content\/uploads\/2025\/04\/job_density_RL-OL.png\" alt=\"\" class=\"wp-image-1134\" srcset=\"https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/job_density_RL-OL.png 1501w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/job_density_RL-OL-300x300.png 300w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/job_density_RL-OL-1024x1024.png 1024w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/job_density_RL-OL-150x150.png 150w, https:\/\/teban54transit.com\/wp-content\/uploads\/2025\/04\/job_density_RL-OL-768x768.png 768w\" sizes=\"auto, (max-width: 1501px) 100vw, 1501px\" \/><figcaption class=\"wp-element-caption\">Employment density map, with both the proposed &#8220;reverse branching&#8221; alignment overlaid.<\/figcaption><\/figure>\n\n\n\n<p>Focus on both sides of Charles River:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>On the Back Bay side, it&#8217;s no competition. Mass Ave merely touches the outskirts of the neighborhood, while the &#8220;Kendall-Back Bay subway&#8221; cuts right through the center of it.<\/li>\n\n\n\n<li>On the Cambridge side, while there are some pharmaceutical companies along Mass Ave and small-scale offices near Central Square (amounting to <strong>~12k jobs<\/strong>), there&#8217;s still more action centered around Kendall\/MIT station. Even excluding MIT and some areas that are similarly further west, the Kendall area still comfortably lands at <strong>~41k jobs<\/strong>.\n<ul class=\"wp-block-list\">\n<li><span class=\"note\">Note that all MIT employers are reported within a single census block, so its ~13k jobs can&#8217;t really be used for a fair comparison.<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n\n\n<p>Here&#8217;s the <a href=\"https:\/\/mbta-massdot.opendata.arcgis.com\/datasets\/d4610a65064a4d3c8536c75d520e0012_0\/explore\">ridership data<\/a> <span class=\"note\">(number of boardings)<\/span> on a typical weekday in Fall 2024:<\/p>\n\n\n\n\n\n<p><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td>Line<\/td><td><\/td><td><strong><span style=\"color:#da291c\">Mass Ave<\/span><\/strong><\/td><td><\/td><td><strong><span style=\"color:#FB99EA\">Kendall-BBY<\/span><\/strong><\/td><\/tr><tr><td>GLX E<\/td><td>Gilman Sq*<br>1,788<\/td><td><span style=\"color:#da291c\">East Somerville*<br>316<\/span><\/td><td><\/td><td><span style=\"color:#FB99EA\">Lechmere<br>1,960<\/span><\/td><\/tr><tr><td>GLX D<\/td><td><\/td><td><span style=\"color:#da291c\">Union Sq*<br>759<\/span><\/td><td><\/td><td><span style=\"color:#FB99EA\">Lechmere<br>1,960<\/span><\/td><\/tr><tr><td>Red<\/td><td>Harvard<br>11,537<\/td><td><span style=\"color:#da291c\">Central<br>9,346<\/span><\/td><td><\/td><td><span style=\"color:#FB99EA\">Kendall<br>9,660<\/span><\/td><\/tr><tr><td>Green B\/C\/D<\/td><td>Kenmore<br>5,879**<\/td><td><span style=\"color:#da291c\">Hynes C.C.<br>7,728<\/span><\/td><td><\/td><td><span style=\"color:#FB99EA\">Copley<br>9,973<\/span><\/td><\/tr><tr><td>Green E<\/td><td>Northeastern<br>724***<\/td><td><span style=\"color:#da291c\">Symphony<br>1,422<\/span><\/td><td>Prudential<br>2,546<\/td><td><span style=\"color:#FB99EA\">Copley<br>9,973<\/span><\/td><\/tr><tr><td>Orange<\/td><td>Ruggles<br>7,979<\/td><td><span style=\"color:#da291c\">Mass Ave<br>3,903<\/span><\/td><td><\/td><td><span style=\"color:#FB99EA\">Back Bay<br>9,912<\/span><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n\n\n<p><span class=\"note\">* While the Mass Ave proposal above doesn&#8217;t extend beyond the Red Line, in order to include Lechmere in this table, I nevertheless &#8220;extrapolated&#8221; corresponding stations on GLX for comparison.<\/span><\/p>\n\n\n\n<p><span class=\"note\">** Likely includes transfers between Green Line branches.<\/span><\/p>\n\n\n\n<p><span class=\"note\">*** Northeastern University has 1,356 alightings. The significant discrepancy between boardings and alightings may be due to methodology and\/or fare evasion. (Note that while East Somerville has 421 alightings, Union Square &#8220;only&#8221; has 664, Gilman &#8220;only&#8221; 1,029 and Lechmere &#8220;only&#8221; 1,525, so the discrepancy for GLX seems inconclusive.)<\/span><\/p>\n\n\n\n\n\n<p>Comparing existing ridership, <span class=\"emph\">the Kendall-BBY alignment beats the Mass Ave alignment one-on-one on each line they cross.<\/span> Sometimes only slightly <span class=\"note\">(Kendall vs. Central; Copley vs. Hynes + Symphony together)<\/span>, and sometimes significantly <span class=\"note\">(Back Bay vs. Mass Ave; Copley vs. Hynes alone)<\/span>. While the overall difference isn&#8217;t decisive, it still means the eastern corridor probably has higher demand.<\/p>\n\n\n\n\n\n<p>On a side note, this also raises another concern for the Mass Ave corridor: What if we move things a bit further <em>west<\/em>? <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Ruggles is obviously a much bigger draw than Mass Ave is. <\/li>\n\n\n\n<li>Kenmore may have lower ridership than Hynes on paper, but if you can hit the big employers in Longwood Medical Area and Boston University, that probably makes up for it.<\/li>\n\n\n\n<li>Bonus points if you can get to Harvard on the Cambridge end, but any of the 3 Red Line stations <span class=\"note\">(and even possibly an infill at Grand Junction)<\/span> may be doable.<\/li>\n<\/ul>\n\n\n\n\n\n\n\n<p>One reason for the popularity of the Mass Ave proposal is the success of the existing Bus Route 1, a Frequent Bus Route that routinely ranks among MBTA&#8217;s most popular bus routes.<\/p>\n\n\n\n<p>The 1 is one of the few bus routes that are closest to my place in Cambridge. I take it fairly often, though not regularly and usually during off-peak. But yes, I jolly well know how crowded it is. Almost every northbound 1 bus gets packed the moment it reaches Hynes Convention Center, regardless of time of the day and day of the week. The sidewalk outside the T.J. Maxx is usually blocked by riders.<\/p>\n\n\n\n<p>But here&#8217;s a <em>personal hypothesis<\/em>: <span class=\"emph\">Many riders of the 1 bus at Hynes &#8212; if not most &#8212; seem to be <strong>walking to\/from nearby areas<\/strong>, instead of transferring to the Green Line.<\/span><\/p>\n\n\n\n<p>While I don&#8217;t have concrete statistics, I often feel that crowds building up in front of the T.J. Maxx mostly come from Newbury St, Boylston St and others. The number of passengers walking up from the Green Line entrance is much smaller than you might expect. Many of them seem to be dining out, shopping, etc.; a chunk of them are students.<\/p>\n\n\n\n<p>Obviously, my experience is not exhaustive, and ridership patterns can differ at other times. But this raises a question: <span class=\"emph\">Could these Hynes riders actually be <strong>heading east to Back Bay<\/strong> instead?<\/span><\/p>\n\n\n\n<p>If that&#8217;s the case, it would argue for more direct access from Cambridge to Copley and\/or Back Bay, rather than Hynes. The latter only has good coverage to half of Back Bay (horizontally); the former covers pretty much all of it.<\/p>\n\n\n\n\n\n<p>I tried to analyze how many riders of the 1 bus at Hynes transferred from the Green Line. However, this analysis didn&#8217;t go anywhere due to fishy data.<\/p>\n\n\n\n<p>The <a href=\"https:\/\/www.ctps.org\/dv\/mbtasurvey2018\/index.html\">2015-17 MBTA Systemwide Passenger Survey<\/a> is the only data source, as far as I know, that breaks down each station&#8217;s ridership by their mode of access. It shows that Hynes station had 5,937 riders walking to the station per day, while <strong>1,650<\/strong> transferred from buses.<\/p>\n\n\n\n<p>However, on an average weekday in <a href=\"https:\/\/mbta-massdot.opendata.arcgis.com\/datasets\/7acd353c1a734eb8a23caf46a0e66b23_0\/explore\">Fall 2017<\/a>, the 1 bus only sees <strong>1374.7<\/strong> riders boarding at Hynes in both directions combined, and 1233 alightings. Transfers to other bus routes at Hynes are likely negligible.<\/p>\n\n\n\n<p>Obviously, it doesn&#8217;t make sense to have 120% of riders on the 1 bus coming from the Green Line. So&#8230;<\/p>\n\n\n\n\n\n\n\n\n\n<p>Personally, these factors sum up my gripes with a Mass Ave service: <span class=\"emph\"><strong>It <em>barely<\/em> hits or <em>barely<\/em> misses several major destinations, and feels like a half-baked way to serve them.<\/strong><\/span> Kendall, Back Bay, Kenmore-Fenway, Ruggles, LMA&#8230; You name it. A route that&#8217;s either just to the east, or just to the west, can serve them more effectively.<\/p>\n\n\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-contrast-2-color has-text-color has-link-color has-small-font-size wp-elements-31b8497edab435d51546f77d03d00bf4\"><em>The only major nodes that Mass Ave directly hits are <strong>MIT<\/strong>, <strong>Boston Medical Center<\/strong> and <strong>South Bay Center (Newmarket)<\/strong>. But MIT&#8217;s campus is already very elongated and doesn&#8217;t favor either Mass Ave or Kendall strongly, while the other two are way too far south and fundamentally a different discussion.<\/em><\/li>\n<\/ul>\n\n\n\n<p>This makes me wonder: <span class=\"emph\">How much of the current successes and future fantasies of Mass Ave are simply because the road exists? <strong>Are our imaginations limited by what&#8217;s already there?<\/strong><\/span><\/p>\n\n\n\n<p>Obviously, if you&#8217;re talking about <span class=\"emph\">BRT or <em>surface<\/em> LRT<\/span> with grade crossings, then Mass Ave is the best we can get. But the moment you consider <span class=\"emph\">grade separation<\/span> and building a tunnel under the widest part of Charles River, <a href=\"http:\/\/archboston.com\/community\/threads\/crazy-transit-pitches.3664\/post-389963\">following Mass Ave may not even net you that much cost savings<\/a>.<\/p>\n\n\n\n<p>Any river crossing here &#8212; minus reusing the existing BU Bridge &#8212; will be expensive anyway. So if you&#8217;re paying that cost, why not do it right, or at least think about if that&#8217;s doing it right?<\/p>\n\n\n\n\n\n<h3 class=\"wp-block-heading\" id=\"12-kendall-bby-vs-urban-ring\">Kendall-BBY vs. Urban Ring<\/h3>\n\n\n\n<p>I&#8217;ll keep this briefer than the previous comparison:<\/p>\n\n\n\n<p><span class=\"emph\"><strong>I do NOT think of a Kendall-Back Bay subway as a <em>replacement<\/em> of Urban Ring. <\/strong>An actual Urban Ring service, in my view, should serve destinations further west: Kenmore\/Fenway\/BU\/Allston, Longwood Medical Area, etc. In a God-mode world, <strong>these two services should co-exist.<\/strong><\/span><\/p>\n\n\n\n\n\n<p>I&#8217;ll first state what I treat as an axiom: An Urban Ring&#8217;s goal isn&#8217;t <em>solely <\/em>to transfer to all radial lines &#8212; it should also bring people to <em><span class=\"emph\">destinations<\/span><\/em> outside downtown, as much as possible.<\/p>\n\n\n\n<p>The following destinations are of interest to the west and southwest:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Back Bay<\/strong> (the neighborhood)\n<ul class=\"wp-block-list\">\n<li>Likely the single busiest place west of Boston Common; &#8220;extended  downtown&#8221;<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Longwood Medical Area (LMA)<\/strong>\n<ul class=\"wp-block-list\">\n<li>The 2nd <span class=\"note\">(or arguably 1st)<\/span> biggest employment center outside of downtown<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Ruggles<\/strong>\n<ul class=\"wp-block-list\">\n<li>Major transfer hub in the area, with bus and regional rail connections<\/li>\n\n\n\n<li>Already used as a proxy for LMA today, thanks to shuttle buses<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>The <strong>Kenmore-Fenway-Boston University<\/strong> region\n<ul class=\"wp-block-list\">\n<li>Kenmore is another transfer hub and road network hub <span class=\"note\">(though the transfer capabilities are somewhat undermined by Green Line branches through-running into the city)<\/span><\/li>\n\n\n\n<li>Boston University (BU) has notable employment and student demands<\/li>\n\n\n\n<li>Fenway borders an urban neighborhood, and of course, Fenway Park<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Allston<\/strong> and <strong>Coolidge Corner<\/strong>\n<ul class=\"wp-block-list\">\n<li>Primarily residential areas with much fewer jobs, but they both have urban neighborhood centers, and Union Sq Allston is a notable cultural center<\/li>\n\n\n\n<li>Already sees successful circumferential transit in Bus Route 66, and a natural road connection (Harvard Ave\/St)<\/li>\n\n\n\n<li>Future developments possible at <strong>West Station<\/strong><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p>The Kendall-Back Bay subway obviously serves Back Bay really well, and it&#8217;s indeed the single most important item on this list. However, <span class=\"emph\">the combined influence of <em>two or more<\/em> other destinations likely outweighs Back Bay alone.<\/span><\/p>\n\n\n\n<p>Another factor is distance: <span class=\"emph\">Back Bay is arguably <strong>&#8220;too close&#8221;<\/strong> to downtown for a ring route to stand out<\/span> (as opposed to transferring in the downtown core). In contrast, some of the nodes further west have <strong>sufficient demand<\/strong> themselves to warrant a dedicated service.<\/p>\n\n\n\n<p>Ultimately, I believe a &#8220;pure&#8221; Urban Ring should <span class=\"emph\">focus primarily on <strong>LMA<\/strong><\/span> in this quadrant. <span class=\"note\">(Unsurprisingly, this is also what the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Urban_Ring_Project\">official Urban Ring proposals<\/a> did.)<\/span><\/p>\n\n\n\n\n\n<h2 class=\"wp-block-heading\" id=\"13-rethinking-back-bays-role-and-even-kendalls\">Rethinking Back Bay&#8217;s role &#8212; and even Kendall&#8217;s<\/h2>\n\n\n\n<p>The discussion above touches on some interesting aspects of Back Bay, though.<\/p>\n\n\n\n<p>In a vacuum, Back Bay alone is more prominent than Kendall alone or LMA alone. <span class=\"emph\">So why has Back Bay not been involved in most Urban Ring discussions so far?<\/span><\/p>\n\n\n\n<p><strong>Distance<\/strong> from downtown may be a reason: Copley Square is around 1 mile from Downtown Crossing (DTX) in straight-line distance, while Kendall is 1.4 miles away. But that alone doesn&#8217;t explain <em>Seaport<\/em> &#8212; another node that&#8217;s often involved in Urban Ring &#8212; which is also 1 mile from DTX.<\/p>\n\n\n\n<p>Personally, the &#8220;real&#8221; underlying reason for me is:<\/p>\n\n\n\n<p><span class=\"emph\">Back Bay feels more like an <strong>&#8220;extended downtown&#8221;<\/strong>, rather than &#8220;outside of downtown&#8221;.<\/span><\/p>\n\n\n\n\n\n<p><strong><span class=\"emph\">Geography<\/span><\/strong>, particularly the lack of water crossings, plays a major role in forming this impression:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Most people define Boston&#8217;s &#8220;downtown core&#8221; as some combination of Shawmut Peninsula, the 4 main transfer stations, Boston Common, and the Financial District.<\/li>\n\n\n\n<li>Radiating out from that area makes you hit bodies of water very quickly in most directions, including towards Kendall, Seaport and others. <\/li>\n\n\n\n<li>But <em>Bacy Bay is one of the few directions where you can go 1 mile entirely on land<\/em>. <span class=\"emph\">It <em>&#8220;feels&#8221; continuous<\/em> from downtown.<\/span><\/li>\n\n\n\n<li>This is made even more saliant by the <a href=\"https:\/\/en.wikipedia.org\/wiki\/High_Spine\">High Spine<\/a>, which was explicitly planned as a continuous chain of skyscrapers linking Back Bay and downtown Boston.<\/li>\n<\/ul>\n\n\n\n\n\n<p>Recent exchanges with <a href=\"https:\/\/railsroadsriverside.com\/\">RailsRoadsRiverside<\/a>, <a href=\"https:\/\/archboston.com\/community\/members\/the-ege.5216\/\">The EGE<\/a> and myself opened up some new, interesting perspectives for me. <span class=\"note\">(Many thanks to them for this section.)<\/span><\/p>\n\n\n\n<p>Back when the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Boston_Elevated_Railway\">Boston Elevated Railway (BERy, <span class=\"note\">the predecessor of MBTA<\/span>)<\/a> first built the Central Subway towards Kenmore in the 1910s, their focus wasn&#8217;t actually on serving Copley Square at all. The original horsecar line and subsequent streetcar lines mostly ran via Marlborough St. <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:1910_map_of_Boston_subway_including_proposed_Riverbank_Subway.jpg\">Initial plans of the &#8220;Kenmore subway&#8221; used the Riverbank<\/a> <span class=\"note\">(today&#8217;s Storrow Dr)<\/span>.<\/p>\n\n\n\n<p>Even though a number of buildings already went up around Copley Square <span class=\"note\">(Trinity Church, Boston Public Library, Old South Church, etc.)<\/span> as early as the 1840s, the area was apparently still not prominent enough to earn an unambiguous transit line through it, until plans changed. <span class=\"emph\">BERy&#8217;s goal was always to <strong>fast track to Kenmore<\/strong>, and communities further west &#8212; <strong>not to serve Copley<\/strong>.<\/span><\/p>\n\n\n\n<p>This gets even more interesting when you look at the history of the three original transit trunks to the west &#8212; today&#8217;s Red Line and both ends of the Green Line:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The trunks were originally intended as direct, rapid connections to <strong>Harvard<\/strong>, <strong>Kenmore<\/strong>, and arguably <strong>Lechmere<\/strong>. These can be considered <strong><span class=\"emph\">&#8220;Inner Belt hubs&#8221;<\/span><\/strong>: They&#8217;re natural diverging points of the road networks, and likewise, explicitly intended to be where streetcar lines diverge onto mixed ROWs. Later, when streetcars were phased out, they became natural transfer hubs where people connect from buses to rapid transit.\n<ul class=\"wp-block-list\">\n<li><span class=\"note\">See <a href=\"https:\/\/railsroadsriverside.com\/the-green-line-turns-100-today\/\">RailsRoadsRiverside&#8217;s pieces<\/a> for more interesting <a href=\"https:\/\/railsroadsriverside.com\/the-kenmore-model-and-the-lechmere-model\/\">discussions<\/a> on this.<\/span><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Arlington<\/strong>, <strong>Charles\/MGH<\/strong> and <strong>Science Park<\/strong> were <em>all<\/em> built as infill stations. Today, we typically consider them as <span class=\"emph\"><strong>&#8220;downtown fringe&#8221;<\/strong><\/span> stations.<\/li>\n\n\n\n<li>What about the intermediate stations, such as <strong>Kendall\/MIT<\/strong> and <strong>Copley<\/strong>? Coincidentally, <em>both almost didn&#8217;t come into existence.<\/em> <span class=\"emph\">How should we categorize them?<\/span>  \n<ul class=\"wp-block-list\">\n<li class=\"has-small-font-size\"><em>There were heavy debates about how many stops should exist between Harvard and Park St. <a href=\"https:\/\/en.wikipedia.org\/wiki\/Red_Line_(MBTA)#Cambridge_tunnel\">Per Wikipedia<\/a>, the City of Cambridge wanted 5 stops, but suburbanites only wanted one: Central. Kendall was essentially added as a compromise.<\/em><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n\n\n<p>This comparison gives us another lens to reconsider not just <strong>Back Bay<\/strong>, but also <strong><span class=\"emph\">Kendall<\/span><\/strong>.<\/p>\n\n\n\n<p>Traditionally, I had always thought of Kendall as an analog of LMA. Both are major employment centers (~70k jobs) that are clearly &#8220;outside of downtown&#8221;.<\/p>\n\n\n\n<p>But now, it seems that <span class=\"emph\">Kendall and Back Bay have a lot in common<\/span>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Their distances to downtown are roughly on the same scale.<\/li>\n\n\n\n<li>Historically, they were both intended as &#8220;stepping stones&#8221; to outer hubs. Even though both stations almost didn&#8217;t exist, the transit access they eventually got has undoubtedly played a huge part in their developments.<\/li>\n\n\n\n<li>Today, they host a similar number of jobs, while taking on varying degrees of non-employment activities <span class=\"note\">(commercial vs. educational)<\/span>.<\/li>\n<\/ul>\n\n\n\n<p>If I had thought of Back Bay and even Seaport as &#8220;extended downtown&#8221;&#8230; <span class=\"emph\">Then why is <strong>Kendall<\/strong> typically considered &#8220;outside of downtown&#8221;, not &#8220;extended downtown&#8221;? Is it simply because of the elephant in the room &#8212; <strong>Charles River<\/strong>?<\/span><\/p>\n\n\n\n<p><span class=\"note\">(This geographical factor definitely affects our <em>perceptions<\/em> today. But I think it might have also affected real-world decision making, specifically in planning of the High Spine.)<\/span><\/p>\n\n\n\n<p>Even though this would seem to argue for adding Back Bay to Urban Ring considerations, I maintain that it might not be a good idea for other reasons. Many other factors are at play: strength of nodes further out, cost, etc.<\/p>\n\n\n\n<p>Regardless, these parallels between Kendall and Back Bay are natural explanations for a fantasy proposal linking them together. <em>The idea didn&#8217;t come out of nowhere.<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"14-why-all-of-this-is-fantasy\">Why All of This is Fantasy<\/h2>\n\n\n\n<p>As I&#8217;ve mentioned repeatedly: <strong>This entire proposal<\/strong> (even the revised Pink Line) <strong>is much less realistic than my typical ones.<\/strong><\/p>\n\n\n\n<p>I am usually a somewhat conservative crayonist. Instead of assuming everything can be brute forced with a tunnel boring machine (TBM) at unlimited cost, I like to keep <strong><span class=\"emph\">cost, engineering and budgets<\/span><\/strong> in consideration. A perfect service plan that costs tens of billions of dollars is worse than a less desirable route that actually gets built. <span class=\"emph\">However, this post is one where I intentionally let go of those constraints.<\/span><\/p>\n\n\n\n<p>The situation gets even more dire for the Kendall-Back Bay subway, in particular:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"15-cost\">Cost<\/h3>\n\n\n\n<p>Long sections of subways will always be expensive. But some are more expensive than others.<\/p>\n\n\n\n\n\n<p>Any underwater crossing in this part of Charles River needs to be at last 2,200 ft long, which is already complex<\/p>\n\n\n\n<p>But the challenges may actually extend to areas under land. <a href=\"http:\/\/archboston.com\/community\/threads\/crazy-transit-pitches.3664\/post-389963\">F-Line to Dudley once stated<\/a> that, due to <span class=\"emph\">soft, low-quality landfill<\/span> in most parts of Cambridgeport south of the Red Line&#8217;s ROW, any subway there has to be <span class=\"emph\">designed almost like a cross-harbor tunnel<\/span> to mitigate lateral movements. It&#8217;s not clear how much this applies to the Boston side of the river, but we do know that almost the entire Back Bay neighborhood was landfilled.<\/p>\n\n\n\n<p>This affects all of:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The Kendall-Back Bay subway<\/li>\n\n\n\n<li>The Mass Ave subway<\/li>\n\n\n\n<li>A subway under Grand Junction (much more popular idea)<\/li>\n<\/ul>\n\n\n\n<p>F-Line thinks that a Mass Ave subway can quite plausibly <em>&#8220;cost just as much as NSRL. And certainly more than any other individual transit project ever.&#8221;<\/em> <\/p>\n\n\n\n<p>I&#8217;m not knowledgeable enough to verify these claims&#8230; But they don&#8217;t paint a bright picture. Keep in mind, the NSRL tunnel is roughly as long as one between Kendall and Back Bay stations, without going under water. The official <a href=\"https:\/\/www.mass.gov\/lists\/north-south-rail-link-feasibility-reassessment-study-documents\">MassDOT NSRL Feasibility Assessment in 2018<\/a> estimated its cost between $12 billion and $22 billion.<\/p>\n\n\n\n<p><span class=\"note\">(If anything, burying a tunnel between Kendall and Dartmouth St may be <em>easier<\/em> than dead under Mass Ave. You&#8217;ll have a lot more space on open water for immersing tubes.)<\/span><\/p>\n\n\n\n\n\n<p>Tunneling under these streets is less of a concern. But even if you ignore possible landfill issues under Dartmouth St, the Back Bay side can still give you serious political concerns, especially if you attempt the cheaper cut and cover (C&amp;C) method that requires digging it up entirely.<\/p>\n\n\n\n<p><span class=\"note\">(One advantage of C&amp;C here, to be fair, is that Dartmouth St has <em>lots<\/em> of cross streets. This might make closing short stretches of the road less disruptive.)<\/span><\/p>\n\n\n\n<p>Then there&#8217;s the challenge of putting a station in Copley Square, surrounded by tons of historical buildings: Old South Church and Boston Public Library immediately to the west, and Trinity Church not far to the east. Given <a href=\"https:\/\/www.bostonherald.com\/2008\/12\/06\/t-official-copley-station-work-likely-to-blame-for-disturbing-church-crack\/\">earlier woes in 2018<\/a> when the Green Line station&#8217;s accessibility work damaged Old South Church, further construction will likely face at least political pushback, if not engineering.<\/p>\n\n\n\n\n\n<p>The Cambridge side of the route may have fewer rich people, but Third St is also narrower (50 ft building-to-building in some sections).<\/p>\n\n\n\n<p>There&#8217;s also the turn from Third St to First St <span class=\"note\">(or at least Second St)<\/span>, where cutting through a block with a TBM is unavoidable, especially for HRT <span class=\"note\">(which doesn&#8217;t have the luxury of allowing tight turns like the Green Line does).<\/span><\/p>\n\n\n\n<p><span class=\"note\">If anything, I&#8217;m wondering if the longer alignment of McGrath &#8211; Land Blvd &#8211; Binney St &#8211; Third St would be better for cutting down costs.<\/span><\/p>\n\n\n\n\n\n<p>To be clear: <span class=\"emph\">A Mass Ave subway faces most of the same challenges.<\/span> Its only significant advantage is avoiding construction in Copley Square and crossing under blocks, but those may not be enough to keep its cost down.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"16-priority\">Priority<\/h3>\n\n\n\n<p>This is probably the bigger concern: <span class=\"emph\">Neither Kendall-Back Bay nor Mass Ave are among the most urgent &#8212; nor most valuable &#8212; alignments here.<\/span><\/p>\n\n\n\n<p>If a new Charles River crossing west of Longfellow Bridge were to be used for rapid transit, it would almost certainly be for <strong>Urban Ring<\/strong>. Despite Back Bay&#8217;s importance in itself, I have to think that any real-world Urban Ring proposal will be further west, with a greater focus on <strong>Longwood Medical Area<\/strong> &#8212; and rightfully so.<\/p>\n\n\n\n<p>Even among alignments for new <strong>downtown<\/strong> trunks, neither rank particularly highly. If exactly one <span class=\"note\">(non-NSRL)<\/span> north-south downtown trunk is built, which is aggressive to begin with, the <strong>Congress St subway<\/strong> seems like a much better choice &#8212; especially for its most likely recipients to the north, Chelsea and Everett.<\/p>\n\n\n\n<p>Lastly, these cross-Charles tunnels may not even be the most valuable <strong>&#8220;cross-harbor tunnels&#8221;<\/strong>. Remember that a Charles crossing near MIT needs to be at least 2,200 ft long? For &#8220;only&#8221; 700 ft more, you can cross <strong>from Seaport to Logan Airport<\/strong>. Such a tunnel would add much more <em>unique, irrepleaceable<\/em> value to the network than a cross-Charles tunnel.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"17-closing-thoughts\">Closing Thoughts<\/h2>\n\n\n\n<p>This idea started as a completely insane exercise: the Orange Line analog for the popular proposal of reverse branching the Red Line. Yet, it actually uncovers some interesting ideas and thought-provoking questions, at least in abstract route planning.<\/p>\n\n\n\n<p>This is not the <a href=\"http:\/\/archboston.com\/community\/threads\/crazy-transit-pitches.3664\/post-470167\">first time<\/a> I&#8217;ve thought about the Kendall-Back Bay subway, but it&#8217;s the first time I&#8217;ve analyzed and reasoned about it in great depth. It made me rethink <span class=\"emph\">the roles of both Kendall and Back Bay<\/span> in the transit network, and more broadly, in the region. The idea also allowed for a more rigorous comparison with the Mass Ave subway, leaving a question that is worth considering for everyone:<\/p>\n\n\n\n<p><span class=\"emph\"><strong>How often are our imaginations limited by what exists today?<\/strong> Not just the existing street grids <span class=\"note\">(as is the case for Mass Ave)<\/span>, but also rail ROWs, and even  other aspects such as developments and demand patterns?<\/span><\/p>\n\n\n\n<p class=\"has-contrast-3-color has-text-color has-link-color wp-elements-c8ab2d2f8ec320cbf47353384577104a\"><em>(As a side note, the question of routing the southern half of the Pink Line also touches on a broader topic: How many new rapid transit routes south of Boston may be desirable? How should we feed them into trunks through downtown Boston? These questions may be addressed in a future post.)<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>TL;DR Background: The &#8220;Mass Ave Red Line&#8221; Proposal You had probably seen this proposal before: Reverse branching the Red Line (RL) via Mass Ave. The motivation is very natural and explains its popularity: Mass Ave, a major north-south road corridor in a region where north-south rapid transit connectivity is scarce, also happens to be on [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":1125,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13,7],"tags":[35,34,36,38,10,39,37],"class_list":["post-1129","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-maps","category-proposals","tag-back-bay","tag-kendall","tag-mass-ave","tag-orange-line","tag-proposal","tag-red-x","tag-urban-ring"],"_links":{"self":[{"href":"https:\/\/teban54transit.com\/index.php?rest_route=\/wp\/v2\/posts\/1129","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/teban54transit.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/teban54transit.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/teban54transit.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/teban54transit.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1129"}],"version-history":[{"count":29,"href":"https:\/\/teban54transit.com\/index.php?rest_route=\/wp\/v2\/posts\/1129\/revisions"}],"predecessor-version":[{"id":1209,"href":"https:\/\/teban54transit.com\/index.php?rest_route=\/wp\/v2\/posts\/1129\/revisions\/1209"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/teban54transit.com\/index.php?rest_route=\/wp\/v2\/media\/1125"}],"wp:attachment":[{"href":"https:\/\/teban54transit.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1129"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/teban54transit.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1129"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/teban54transit.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1129"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}