You may be wondering why I never followed up on my promise to simulate Regional Rail ridership for the Providence Line. In part that’s because it’s actually really hard — the Providence Line is much more complicated than the Worcester Line in terms of the number of services it must integrate (Amtrak, Stoughton Line, Franklin Line), the weird set of short-turns, service into central Rhode Island, and the sheer number of passengers (it is the MBTA’s heaviest-ridership commuter-rail line). I’ll get back to that soon, I hope. But the primary reason, as the title of this post suggests, is that I’ve been doing a lot of thinking about buses.

I made a Google Map showing the nine MBTA bus routes which serve more than 10,000 passengers per weekday (counting the SL4 and SL5, which overlap for most of their route along Washington Street from Dudley station to downtown, as a single route). The busiest route in the entire system is the 28, a former streetcar route connecting Mattapan to Grove Hall and Dudley, with many trips extending to Ruggles station, serving 12,880 passengers on 233 bus trips per weekday. Based on the (2017) system-wide average operating cost information the MBTA has reported to the Federal Transit Administration and the route-specific information reported in the Better Bus Project‘s route profiles, I guesstimated that this route costs approximately $7.5 million a year to operate. Other routes connecting southern Dorchester to northern Roxbury serve similar numbers of riders and have significant route overlap, including the 22 (Ashmont–Ruggles via Columbus Ave., 8,020 riders), 23 (Ashmont–Ruggles via Dudley, 11,810 riders), 29 (Mattapan–Ruggles via Columbus Ave., 2,250 riders), 21 (Ashmont–Forest Hills via Morton St., 4,290 riders), and 31 (Mattapan–Forest Hills via Morton St., 6,100 riders) — all told, 1,168 bus trips per weekday serving 45,350 people a day. (That’s more than the entire system-wide ridership of any of the state’s 11 Regional Transit Authorities — PVTA comes closest, at 39,368 average weekday riders.)

In any other city, a ridership of more than 10,000 passengers per weekday — 2.6 million riders a year — would more than justify a shift to a higher quality transit mode. But of course this is Boston, and all of those routes serve minority communities, so they have been stuck with diesel buses since the trolleybuses (which replaced the original streetcars) were moved to Cambridge in the 1950s. (They replaced streetcars in Cambridge, too — the trolleybus routes that currently operate from North Cambridge carhouse were originally bustituted to free up streetcars to operate the then-new Riverside Line through Brookline and Newton.) Taken together, this particular set of bus routes serves on the order of 11.8 million riders per year. (This number can only be approximate because what we are actually counting is not really rides or riders but so-called “unlinked trips”, which is a single ride on a single bus, and therefore double-counts transfers.) Surely this would justify a substantial capital investment to get those people to where they need to go faster, in greater comfort, and at lower operating expense?

It was time to start seriously looking at the map. It was pretty clear how a modern tramway would fit along the route of the 29: Blue Hill Ave., Seaver St., Columbus Ave., and Tremont St. are all at least 80 feet wide and could easily support a center reservation. But the 29, again, only serves a couple thousand riders and doesn’t run frequently enough to justify the conversion on its own. The MBTA even admits that the 29 only exists to save riders the trouble of transferring from the 28 to the more frequent 22. The 31 runs very frequently, and would share part of the 29’s reservation, but again, it only serves 6,100 riders a day, which (while it would be excellent for a “new streetcar” project in most of the US) doesn’t really justify the investment here. The Ashmont routes are even worse — the streets of Dorchester are for the most part only forty feet wide, which is barely wide enough for a reservation and two-way car traffic with no parking; when these routes were streetcars before, they ran in mixed traffic (which was of course much lighter 80 years ago than it is today), and a big part of the benefit of tram conversion would be getting out of mixed traffic if not complete grade separation. So I put this speculation aside.

There is one route, however, which has no such issues — but it’s not one of the Dorchester routes, it’s the SL5, part of the “Silver Line”, which was marketed as “bus rapid transit” at a time when the Federal Transit Administration was strongly favoring such projects. The main segment of the “Silver Line”, the South Boston Piers Transitway, was built as a part of the Central Artery/Tunnel Project, and includes a dedicated bus tunnel under Fort Point Channel from South Station to South Boston; because this tunnel lacks ventilation it is restricted to electric buses only, and in practice is operated with 60-foot dual-mode trolleybuses. The SL5, however, is different. It (and its companion route the SL4) were created to respond to the demand of the Roxbury community for a service along Washington Street that was “better than a bus” after the Orange Line was relocated from the Washington Street Elevated to the Southwest Corridor to the west in 1987. The SL4/5 operate frequent service with 60-foot diesel buses, and the route along Washington St. is theoretically a reserved bus lane although the markings are poorly maintained and rarely enforced. The rest of the route is in mixed traffic, which affects the SL4 (to South Station) more than the SL5 (to Park Street and Boylston stations).

There is a subway tunnel underneath Tremont Street — part of the original Tremont Street Tunnel, in fact — which was last used by streetcars in the 1940s. It even has a flying junction at the south end to speed cars diverging to South Boston (the #9 City Point route used to run this way) and Roxbury. For a while, the state was studying converting this perfectly good rail tunnel into a bus tunnel, but ultimately decided it would be too expensive. (This was tied up with constructing a new bus tunnel all the way to South Station, parallel to the Red Line, because buses are just so awesome.) The old tunnel portal (currently blocked by a park) is barely a block from Washington Street, and pretty much every advocate for “Washington Street replacement service” since the 1980s has been demanding that the T create a new F branch of the Green Line to serve Dudley along this old streetcar corridor.

Sandy Johnston (@sandypsj) pointed out on Twitter how the Portland Streetcar, which opened 20 years ago, was able to use a modern construction technique that significantly reduced the cost of construction by reducing the amount of concrete required for the trackbed (and thus the depth of the excavation and the amount of utility relocation required). That doesn’t solve the issue with street width, but perhaps it could make the construction of a new reservation cheap enough to justify the project just on that basis. And certainly for replacing the SL4/5 it might be worth the expense.

The MBTA is currently engaged in a “Bus Network Redesign” project. The T also just approved a very unambitious 20-year capital program, and is working on replacing or renovating all of its ancient and inadequate bus garages. And it’s also working on modernizing the Ashmont–Mattapan High Speed Line, which is currently operating using five-times-overhauled PCC streetcars from the 1940s. At the MBTA board meetings I’ve attended or watched recordings of, there is considerable frustration at the fact that the T is essentially unable to increase bus service at peak periods because it has no space in its bus garages to park or maintain additional buses. I started thinking again about replacing high-ridership bus routes with tram routes, wondering if the project could be justified solely on the basis of reduced operating costs (trams have larger capacity and so could operate less frequently, alleviating bunching and congestion at major stations like Ashmont and Dudley) and freeing up buses and garage space for other routes that are less practical to restore trams on.

I spent several more hours staring at maps and trying to think of which of these bus routes, when considered together as a complete system, would make sense as part of modern tramway system, assuming the T could somehow manage to build something for a reasonable cost and in a reasonable time, with the goal of eliminating the need for an entire bus garage worth of buses and representing an overall operating cost savings to the T. The F-Dudley extension is a somewhat different case, because for schedule adherence (which matters a great deal for capacity in the parts of the Tremont St. Subway that are shared with the existing Green Line branches) you don’t really want to interline it with the other routes, except maybe off-peak on weekends and holidays when it could interline with the 28, so the assumption would be that it would take over one of the two GLX branches and its rolling stock could be stored at Lechmere where a new carhouse is being built to support GLX anyway. In any event, I came up with five distinct sets of projects:

• Roxbury–Dorchester system: routes 22, 23, 28, and 29, including three of the highest-demand routes in the entire system (22, 23 and 28), representing 35,000 daily riders, and approximately 460 revenue bus-hours of service on today’s schedule. The 22 operates 188 trips per day, the 23 runs 250 trips, the 28 runs 233 trips, and the 29 a mere 77 trips. Nearly all of the 28 route is on streets that are wide enough for a full reservation, so with better stop spacing and signal priority, a large fraction of the 28’s nearly 13,000 daily riders should experience reduced trip times. The 22 and 23 would see less benefit, because more of their route is in mixed traffic. The overlap between the 22 and the 29 is substantial, however, and more than half of the 22’s length would be in a reservation along Blue Hill Ave, Seaver St., and Columbus Ave.
• Roxbury supplemental routes: the 44 and 45 have substantial overlap with the the first set of routes, enough that I thought it was worth including them in my plan even though the ridership (3,450 on the 44; 3,140 on the 45) and vehicle requirements (98 bus revenue hours) hardly justify tramification. On the other hand, these routes serve mainly transit-dependent passengers and could have a real positive impact in those neighborhoods. However, they would be operating in mixed traffic on narrow streets.
• Forest Hills system: routes 21, 31, 32, and 42 all converge on Forest Hills station in Jamaica Plain. When routes in this area were streetcars, they were served by Arborway carhouse on Washington St., which is a bus garage today. The 32 is one of the most frequent bus routes in the system, running from Wolcott Square in Readville, next to Readville commuter rail station, to Forest Hills, nearly entirely on Hyde Park Ave. Only the northern part of HPA is amenable to a reservation; the southern part (roughly, south of American Legion Hwy.) would be in mixed traffic. Roughly half of all 32 runs are short-turns from/to Cleary Square, next to Hyde Park commuter rail station, but in my estimation of operating hours and costs I have not accounted for this, so the numbers I have for operating costs on the route are not to be trusted. The 42 is another lower-volume (2,560 riders) route, but it runs straight along Washington St. between Forest Hills and Dudley, so it provides a connection between the two systems; it would however cost significantly more to operate than the current bus unless the schedule was cut back to the point of uselessness. Finally, the 21 and 31 connect Ashmont and Mattapan to Forest Hills via Morton St. and the Arborway; the 31 would operate mostly in a reservation, but east of Blue Hill Ave., Morton St., Gallivan Blvd., and Dorchester Ave. are too narrow to build a reservation so that half of the 21 route would be in mixed traffic.
• E-Arborway restoration: route 39 was instituted to provide service along the E Line between Heath St. and Forest Hills when the E branch was truncated in 1985. Restoring the E Line was a Central Artery Project mitigation commitment which the state reneged on when business owners in Jamaica Plain objected to the loss of “their” on-street private vehicle storage that would be required to make the E fully accessible. A decade ago, the City of Boston tore up the tracks and repaved South Huntington Ave., Centre St., and South St., making any service restoration much more difficult. (The overhead electrification was trolley wire and would have had to be replaced in order to support modern trams.) In recent years, Boston has partially repented and asked for the restoration of the line as far as Hyde Square, and an anonymous guest post on Ari Ofsevit’s blog talks about the practicalities in doing that in much greater detail. For the purposes of this analysis, however, I considered complete restoration of the service, which would allow allow the E Line to again be based at Arborway.
• F-Dudley branch: finally, as previewed above, I am most strongly advocating for a replacement of SL4 and SL5 service with a new F-Dudley Green Line branch. Moving the E Line back to Arborway would free up enough storage space at Lechmere carhouse to allow all of these trams to be stored there, and as the F would be by far the shortest route south of downtown, it would make sense to pair it with the longer of the two GLX branches, to Tufts and eventually Mystic Valley Parkway. In order to make enough capacity in the subway between Park and Government Center, one of the existing branches would need to loop at Park during peak hours; since the B Line is the longest south/west branch in running time, it makes sense for it to be the one.

In order to get any meaningful travel-time savings, it’s necessary to do something about the bottleneck along Warren St. between Grove Hall and Boston Latin Academy. Like Washington St. and Talbot Ave. in Dorchester, Warren St. is only 40 feet wide until you get north of Quincy St. — but it’s a very important and heavily traveled street, and most of the congestion-related delays experienced by the 28 happen in this section. I strongly suspect it would be highly unpopular to completely eliminate on-street parking in this stretch of road, never mind eliminating car traffic entirely, which is probably the environmentally superior option; there are no parallel surface streets, the east-west streets in the area are primarily residential, and residents of Quincy St. in particular would not welcome the additional traffic. Having ruled out any plausible surface route, I decided to propose a shallow, cut-and-cover tunnel. The state would not under ordinary circumstances make that sort of investment in an area that is predominantly inhabited by lower-income people of color with little political influence, but perhaps now with representation in Congress (Roxbury and most of Dorchester are in Rep. Ayanna Pressley’s district) the winds could shift.

In this exercise, I’ve started from the counterfactual “What if the MBTA was competent at capital construction?” As a result, I’ve assumed the use of modern, Euro-spec trams and reasonable costs for tramway construction. However, tunneling is a different story altogether. If the costs of bored tunnel construction were at all reasonable, I might propose a whole new subway line, taking over the route of the 23 — but they’re not, especially not in the US. Even cut-and-cover tunnels are still quite expensive, as it happens, and for a short bypass tunnel of ¾ mile of Warren St., that’s the low-cost construction technique. That’s also the one tunnel segment that would benefit the most people on the entire surface network.

So I collected a lot of data, traced out routes and stops using the distance-measuring tool, and tried to guess what the operating costs of these routes are today as buses and would be as tram routes, based mostly on public data. I collated all of this data in a Google spreadsheet so you can check my work, laugh at my unrealistic assumptions, etc. Unsurprisingly, since these heavily traveled routes account for a lot of bus trips per day, they also cost a lot to operate — although the 21, somewhat surprisingly, seems to be profitable. For operating costs, I first estimated the number of revenue hours and revenue miles from the Better Bus route profile (which gives a breakdown of trips by daypart and also has a section that shows the actual operating time of each route compared with the scheduled running time). Using the 2017 summary data page from the National Transit Database, I estimated the operating costs for each route as the average of the per-mile and per-hour costs — since those costs are given as system-wide averages the actual per-route numbers might well be much higher or lower than what I’ve calculated. I computed the replacement tram running time based on a formula that accounts for lower average speed of mixed-traffic operations (approximately equal to that of a bus) and a 30-second stop penalty for each stop taken (for some routes, applying a stop factor to account for not all stops being taken on every trip). I chose service levels on the tram routes to generally ensure a comparable level of comfort for current bus passengers while reducing the number of trips to account for the higher capacity of 90-foot trams over 40-foot buses.

On the basis of these calculations, I concluded that the current service on these routes costs nearly $54 million annually to operate (that’s not counting capital costs for new buses or bus garages, because transit agencies do not take depreciation charge-offs). On the basis of my tram operating schedule and the current hourly cost of Green Line operations (again taken from the 2017 NTD summary page), I calculated that a full build would save $13.2 million annually in operating expenses, nearly a quarter. If the less used 42, 44, and 45 routes were left as buses rather than converted to trams, the savings increases to $15.2 million. Of the remaining routes, the E-Arborway restoration alone accounts for $3.8 million of savings annually, and replacing the SL4 and SL5 with a new F-Dudley is worth another $1.7m. (Of course the full-system numbers need to be discounted for the issue with route 32 short turns that I discussed above.)

So what about those capital costs? That’s where it starts to get sad. Even with very optimistic assumptions about construction costs, and assuming only $350 million per mile of tunnel, the full-build scenario costs nearly $1.8 billion — and let’s be brutally honest, the MBTA is never going to spend that much money on poor brown people in the city. (It doesn’t even want to spend that much money on barely-acceptable-by-European-standards commuter rail service that mainly serves rich white people like me.) That would be $19,240 per passenger. Even dropping the tunnel doesn’t help much; assuming you could magick away the on-street car storage and build a reservation down one side of Warren St., that only drops the price by 16%, to just over $1.5 billion. I still think it’s worth doing, but it seems like a really hard slog. (And if you could actually get nearly $2 billion for Roxbury and Dorchester, again you’d probably be better off building a new bored-tunnel subway that wouldn’t need to line up with the street layout.)

But the two easiest cases I have to make would be for restoring the E Line to Arborway (eliminating the 39 bus entirely) and building the F Line. I put a bit more effort into breaking these out, because the numbers look quite favorable (although I’m not convinced they’d pass an equity analysis). Both of these projects have significant unknowns: for the E Line, it’s the cost of making the existing E Line stops fully accessible, and for the F Line, it’s the cost of rehabilitating the Tremont St. Tunnel, making Boylston Station accessible, and reopening the old portal. I don’t have a good idea what these would cost, although the accessibility improvements are already in various long-term plans. Beyond these unknowns, I also assumed the use of new Type 9 LRVs — if the MBTA actually committed to doing either project in a reasonable time (which is much sooner than they are capable of deciding to tie their shoelaces at present) then they could just tack on a few more cars to the existing Type 9 order being built by Spain’s CAF (and assembled in New York State), which is a cost that we do actually know. On that basis, I estimated the surface parts of the F-Dudley at $122.4 million, or $7,600 per passenger per weekday, and the E-Arborway at a slightly higher $115.2 million ($9,930 per passenger). These numbers seem a lot more reasonable, but still difficult to get FTA funding for.

You can see all of these numbers and the formulas used to calculate them on the “Summary” tab of my spreadsheet. That’s all I have time for now, so I’m going to put this project aside and go back to thinking about Regional Rail.