A Good Problem for the El

The Market-Frankford Line has a capacity issue. It's crowded during rush hour. And its crowding isn't just in Center City, it's end-to-end. Many people use the el to connect to the NHSL, 101 and 102 trolleys, and buses points west at 69th St., and buses points northeast at Frankford and Arrot terminals transportation centers. And with a ridership of just over 190,000 ppd, it is by far SEPTA's single busiest route, one that sees a surprising 60% more riders than the Broad Street Line.

Crowding indicates the el needs more space. As heavy rail -- infrastructurally, by far the highest-capacity of all modes -- any further capacity increases must come with relatively incremental improvements to the current physical plant. Some improvements are cheaper than others. A couple can be implemented immediately; others may take a little while longer. From cheapest to most expensive, we can:

- Use longitudinal seating. This one is by far the cheapest way to increase capacity, requiring nothing more than a refurbishment of the el cars' interiors, one which (they are halfway through their design lives) they are due for soon. It's also used in several other American subways -- notably, Boston and New York. Longitudinal seating decreases seating capacity, but it makes up for it by increasing standing capacity; it's also important to notice that in the current setup, the worst crowding occurs around the doors; longitudinal seating can help alleviate that.

- Convert to automatic train control (ATC). The el, like New York's 7 and L trains, is a single line with no branching. While no US transit agency has demonstrated the expertise to more than ~25 tph with human-driven subways (the MTA tried once and it failed miserably), ATC allows trains to be programmed to run at any frequency so desired. Increasing the frequency increases the runs a given trainset can make, which in turn increases overall line capacity. Indeed, when the 7's ATC installation is finished later this year, the line's peak frequency will be 28 or 29 tph -- just shy of one every other minute.

- Use full vestibules. There's a lot of unused space between the el's train cars. Use of full vestibules -- essentially, an articulating chamber between the cars (much like the one on articulated buses) -- would add a lot of usable space within the boundaries of the train. 10% more, in fact. Fun fact: full vestibules are now found on metros in every single country that uses them ... except the US.

The problem with this is that the current equipment is halfway through its life cycle and full vestibules would have to be a design requirement for their replacements. It would also require a rethink of el trains from a triplet of married pairs back-to-back-to-back to a single six-car unit. Indeed, thinking of trains as assemblages of cars rather than unitary bodies in their own right is often cited as the main reason why the US (whose railroad engineering expertise stalled in the 1950s) doesn't use full vestibules.

One can also argue that a full-vestibuled trainset naturally locks train length in for the duration of its life cycle. But that is only an issue if we are actively pursuing infrastructure for longer trains.

- Lengthen the platforms. Another way to increase the el's train capacity is, naturally, to use longer trains! But train length is currently proscribed by the length of the system's shortest platforms: therefore, it makes sense to increase platform lengths if we want to, well, platform longer trains. This is particularly problematic on the West Philadelphia elevated, whose platforms should have been extended to handle seven- or possibly eight-car trains in the recent rebuilding; the 2nd, 5th, 8th, and 11th St el stops, which can can only platform six cars and require tunneling to increase platform lengths; and the 69th St Terminal Transportation Center, where the track design of both platform approaches may well actually preclude any lengthening. Easier are the Frankford el's shorter platforms, which are now more than 20 years old and can conceivably be rebuilt to handle longer trains during a modernization program in the not-too-distant future.

The downside of this is that, if you're already using full vestibules, the benefits of lengthening the platforms comes not when you've lengthened the shortest platform, but rather once you've replaced the trainsets with ones that take full advantage of the longer platforms. Of course, this can be spun: Great! Our new self-driving, longitudinal-seating full-vestibuled trains increase capacity by some 25%! Now we have some thirty-forty years to lengthen all the platforms so that we can run longer trains and further alleviate crowding now that the easy stuff's done!

- Build an express track. This is perhaps the most difficult of the incremental investments. While the original plan for the el was for it to run express through Center City, and the trolleys local -- the trolley tunnel from 15th to 32nd being therefore incorporatable into an express line -- PRT, the el's original builder, was never able to finish the scheme, having run out of money by the time the line reached City Hall and only able to raise enough to build half of the system for the last (and most expensive) mile. As a result, the West Philadelphia and Frankford els were never designed to incorporate an express track, and there's a fair possibility the latter may not be able to, either. (Market Street is much wider, so you've got more room to work with.)

All that said, the fact that el crowding doesn't drop off as you head further out, but is rather end-to-end, makes it useful to look at an express track (perhaps as a couple of short segments of timed overtakes?) Such a track would offer a useful second service for passengers heading to 69th St or Frankford and thereby free up local capacity for interstitial stations.

- Build an interceptor line. Not remotely incremental, this -- by far the most expensive solution of all -- builds a new line that siphons off some of the el's traffic at its source. Built as planned, a Boulevard subway would function as this: it would intercept most of the traffic on the 14 bus and near the Boulevard, as well as (assuming a convenient transfer) buses on Bustleton, Oxford, and Castor avenues, leaving primarily the 66 feeding into the el.

Interceptors would also have to function as lines in their own right. This is either a feature or a bug: by intercepting most passengers taking the train to Frankford, you've opened up a lot of capacity. Capacity that can get filled up. In fact, the Media/Elwyn and Paoli/Thorndale Lines are both arguably interceptors for the el (via the 101 and 102 for the former, and the NHSL and 105 for the latter) ... and are themselves heavily used. Essentially, patronage has expanded not just to fill the core line but the lines built to alleviate capacity by intercepting it.

The Boulevard subway was last projected to have the same passenger counts the el today "enjoys", a fair percentage being intercepted el passengers. But it's more than likely that that capacity would quickly get filled up, and the el run at capacity again.

So it's good to think of new lines, and think of new lines not just in their own right, but how they would fit into the network; but to propose a new line solely to alleviate the capacity problems of another is not so good an idea. Induced demand is just as true for mass transit as it is for cars and bikes.

Modifying Center City's Market Street Tunnel

Built in 1907 (and extended during the Great Depression), Center City's Market Street tunnel is an example both of the possibilities and the realities of the subway. Originally envisioned as an express subway-local trolley tunnel, the Philadelphia Rapid Transit Corp. (PRT) ran out of money less than halfway through construction from the original 23rd St. portal and was forced to terminate the trolleys at City Hall, resulting in a situation where all subways have to run local east of it, stopping at 13th, 11th, 8th, 5th, and 2nd Streets, while not stopping at all along the axis of postwar skyscraper development along Market west of City Hall.

Never a great fit, even in the best of times, the Market-Frankford Line now stops too frequently, particularly in Market East (where two, rather than three, stops are really called for), or not at all, relative to Center City's major employment and retail destinations*. The trolley transfer at 15th is confusing (you have to access the westbound trolley platform, from 15th, via the Broad Street Line platform), and a full subway stop--not just a local trolley stop--at 19th is necessary to capitalize on the strong demand for Penn Center, Logan Square, and Rittenhouse Square access.

Fixes for this are, needless to say, expensive.

The easiest-to-implement partial "solution" to Market East's too-close-together subway stops is to implement stop-skip service at 11th and 13th, much as occurs elsewhere in the system (particularly on the Frankford Elevated). The free trolley transfer at 13th can also be done at 15th (despite its complexity) and 30th, making it a relatively minor loss if half of the rush-hour trains don't stop there, and the line's stop-skip service has been in use for so long that it's fairly simple just to add an extra "A" and "B" to the map. However--this is still a quick fix, a half-assed solution. And it doesn't remotely address the issue of unmet express-service demand along Market West.

To optimize the tunnel, relative to today's use patterns, would require (a) the consolidation of the 11th and 13th Street stations into a single stop**--certainly feasible from a technical standpoint; the tunnel is mirrored on either side by a pedestrian tunnel; and so opening the pedestrian tunnel to the rail tracks at 12th, along with adding some new fare gates and punching an entrance into the former Reading Terminal's basement, along with some barricades along the former 11th and 13th Street platform edges--nothing too fancy, but nothing ugly--along with a fare-gated passage down to the Juniper station, to maintain the free transfer. This costs some money, of course, but is relatively inexpensive--probably about the same as the already-needed-anyway refurbishment of '70s-garish 11th Street Station.

Market West, on the opposite side, is much more expensive. There the need is to widen the tunnel approximately 10 feet from the western side of the current 19th Street station down to 20th; and were a new 19th Street trolley station elected to be built, two new platform niches for that, too. Like at 30th, the maximal cross-section for a full stop could be as much as 80 feet (Market is 100 feet wide), requiring significant utilities relocation in an underground that is more like Swiss cheese than schist. Furthermore, a new second-level concourse would need to be bored under the rail tunnel; access to an MFL platform without it is impossible. The most cost-effective solution may be to maintain the current 19th Street carstop with a deep new elevator niche and fare barrier*** and access to the sublevel concourse at its western end^, coupled with a brand-new concourse access at 20th^^. Either way, retrofitting an existing four-track subway for a new express stop cannot be cheap.

UPDATE: It occurs to me that this discussion is incomplete without a discussion of 30th Street access improvements. Currently, there is no direct route between the main station and the subway concourse^^^; there used to be one that followed an indirect and winding route, but that has long since been closed, with one entrance being obscured by a pub.

An obvious immediate improvement is to cover the (heavily used) pathway between the main station and subway concourse.

In the longer term, the major access issues are caused by the layout of the area. There is little space to effect direct access; this, indeed, was the reason the original implementation was winding and circuitous, which led to its lack of safety and eventual closure. The only good spot to extend the underground concourse in such a manner as to create a direct connection with the main (intercity) station is currently occupied by the lower level of 30th Street, a route which is also an access road to the coach yards on the north side of the station. The obvious answer to this conundrum is to open a new access path to the coach yards, allowing this access road to be closed and the concourse extended across it towards a direct station connection.

But what if it can't be? Not in the short or medium terms, at least?

A good medium-term plan to offer direct main station-to-concourse access at 30th may be to enclose a pathway connecting the main station to the concourse along the side of this quite wide lower level, with a sort of gated ped-road crossing (as an access road, it's lightly used) where the pedestrian access pathway must needs cross the carriageway. Moveable glass fixtures may be used, allowing the pathway to be climate controlled. No matter what the solution is, however, the space must be well lit and securitized. It must be safe and feel safe. Safety (or the perception thereof) was what did the previous connection in, in the end; just as important as solving access issues is the solving of safety issues in the area.
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* Those actually fronting Market Street, remember.
** Why this was not done in the first place, I have no idea. The closest stop to the former Reading Terminal would have been 11th; it is frankly bizarre that there was never direct subway station access. 11th and 13th were obviously built to facilitate department store access (Wanamaker's at 13th; Snellenburg's and Frank & Seder at 11th), but access would still have been possible at 12th, particularly since pedestrian tunnels have been built parallel to the subway from 11th Street west. (These, note, are almost certainly later additions.)
*** Cheaper than a niche for a whole carstop, that's for sure.
^ This setup also has the advantage of making the existing carstop an access concourse for a potential 19th Street subway. The MFL concourse would then terminate in the new line's southbound platform, while the northbound platform would be accessed from the carstop's east end.
^^ This is assuming that the El stop would be built between 19th and 20th Streets. A case can also be made for locating Market West between 18th and 19th Streets, in which case just switch all my "wests" to "easts" and "easts" to "wests" and provision for access to the Penn Center concourse (currently terminating in the BNY Mellon Building at 18th and Market). 19th-20th is more equidistant between 15th and 30th; 18th-19th has better connections access and is slightly closer to the major draws.
^^^ A perception issue as much as anything else. Cities without these sorts of connections just don't quite feel large and worldly--whatever the reality may be. As an example: New York's Grand Central Terminal and Penn Station, Boston's North and South Stations, and D.C.'s Union Station all have these interconnections. Camden and Penn Stations, Baltimore, by contrast, do not.

Extending the Market-Frankford Line

This is another post in the Philadelphia2050 series.

The Market-Frankford Line (locally called the "el") is the busiest heavy-rail route in Philadelphia, with some 180,000 daily riders, a number that compares favorably with anything the CTA, MTA, WMATA, or MBTA could put forward. It is a broad-gauge line using under-rail contact third-rail electrification, a setup totally unique in the United States, and its dynamic envelope is somewhat narrower than the Broad Street Line's. The line doesn't have any express tracks, and in fact, its daily operation pattern is near-optimized given its constraints. Its current trains are 8 cars, the same length as the line's shortest station, 5th Street; lengthening this station might allow longer trains, certainly necessary given the line's frequent crush loads.

The line currently terminates at Frankford Transportation Center in the near Northeast; while the capacity constraints laid out above prevent it from being used as a Northeast subway, a relatively short extension may be used to help the capacity problem.

This extension would involve a connection with the proposed Roosevelt Boulevard subway at Bustleton Avenue. Since the Boulevard subway would connect into the Broad Street tunnel, which does have express tracks, and a surprisingly high proportion of el riders go from Center City to the Northeast, with a transfer at Frankford, this expansion would be integrated into the Phase I construction of the Boulevard line in order to hopefully cut the el's ridership some--as I mentioned, congestion is an issue at peak hours, when train cars are beyond SRO and simply packed to gills.

The second part of this extension is an extension to place. The corner of Cottman and Roosevelt is one of the major retail centers of the Northeast, and the el extension there simplifies access to place. With improved access, of course, densification of the heart of the corridor--the stretch of Cottman from the Boulevard through Bustleton to Castor, would be encouraged. Also of interest: the proximity of this stretch of Cottman to Pennypack Park suggests a possible sub-use as a bicycling trailhead.

The three new stops (Roosevelt Bvld., Tyson, and Roosevelt Mall) would be expected to generate some new traffic, but this is counteracted by the siphoning effect of the major junction at the Boulevard and Bustleton. A study earlier this decade suggested that a Boulevard subway would have as many as 300,000 daily riders; this extension, being limited in scope, would have far less.