Amtrak’s announcement that it needs $7 billion to improve Union Station, in a way that is tangential to train or passenger capacity, has gotten some deserved flak already on other blogs. What I want to discuss instead is a pair of issues relating to capacity: passenger circulation, and track capacity. Especially on the latter, Union Station does have some problems, not at current traffic, but enough that future traffic increases may require difficult at-grade merges. The core of the problem is that the terminal tracks are located to the west of the through-tracks, with an at-grade junction, rather than between them.
Fortunately, the passenger circulation capacity issue is easier. Although Amtrak claims 100,000 passengers use the station every day, in reality the number is beefed up with Metro riders, similarly to Penn Station’s 600,000 daily passengers statistic, of which nearly half is subway ridership. Total ridership on MARC and VRE is 53,000 per weekday, and Amtrak has a total of 13,000 boardings and alightings per day there (not per weekday, but intercity traffic does not have the weekday peak of commuter traffic). This is 66,000 boardings and alightings, assuming every MARC and VRE trip begins or ends at Union Station. In contrast, on just two tracks with ordinary subway platforms, Metro has 34,000 boardings at the station; page 13 of Amtrak’s announcement shows the relative scale of Metro and mainline infrastructure. The mainline half of the station’s ridership is passengers who are likelier to be carrying luggage or not be local, but the main difference between it and the Metro half is that the Metro half is using Metro turf and the mainline half is using the station above which Amtrak’s headquarters is located.
If there is a problem, it comes from Amtrak’s practice of corralling riders at waiting points, instead of letting them filter onto the platforms or the stations whenever they like, as is done every day on trains in France and Germany, or on the less busy stations of the Northeast Corridor. Stephen Smith tells me that unlike in New York or Boston, where the waiting areas are at least adjacent to the platform and the problem is one of having just one access point (or just one official access point in New York), in Washington there is another antechamber between the passengers and the train. An extra 100 meters of walking adds about a minute of travel time in a congested space, and perhaps 45 seconds in a clear one; Amtrak’s current practice adds multiple minutes to door-to-door travel time, and also forces pedestrian congestion once it clears passengers to access the platform.
Adding access points is also a good thing, but that does not cost $7 billion, and does not require redoing the entire main concourse. But possibly the most important thing to do in the near term is making all platforms high, also nowhere near a $7 billion project; the diagrams on Amtrak’s announcement suggest all terminal tracks and most through-tracks will be high-platform, but one through-platform will remain low.
Now, track capacity is where things get more interesting, because potentially there is a problem, coming from terminal layout. A not very clear, but public, diagram can be found here: look for Washington Union Terminal, and within it, Interlockings C (the outer station throat and a nearby yard), K (the inner throat and the actual tracks), and A (the connection from the through-tracks to First Street Tunnel). Note that terminating tracks 7-20 are to the west of through-tracks 22-29, and the junction is at grade, which represents a problem for easy cookie-cutter planning.
The operationally simplest but most expensive to deal with this is to build a grade separation. If it’s anything like Harold, expect a $300 million price tag. At present and expected levels of traffic, this is overkill.
I claim that if MARC and VRE trains continue to terminate at Union Station, no special work is needed: Brunswick and Camden Line traffic can be segregated on tracks 7-9 (and the turnaround capacity, easily about 12 tph for 3 tracks, is more than those lines will need between them), VRE traffic can be segregated on tracks 24-25, and Penn Line traffic can use the same tracks as the terminating intercity trains.
The only at-grade conflict would be between northbound trains originating at Washington, and southbound ones continuing through to Virginia, and even high possible traffic levels (say, 12 tph terminating including the Penn Line sprawled across 11 tracks of which 3 already have long platforms and arguably 3 more can be lengthened, 2 tph through across 4 tracks) can be scheduled in a similar manner to all-terminating stations, treating the through-trains as terminating trains that have to use specific tracks and have no limit on dwell time.
Specifically, because Penn Line (or local HSR) trains would leave immediately after express HSR trains to reduce the number of required overtakes, at worst we’d have trains originating at :00 and :02, repeating every 10 minutes, and then there’s an 8-minute window within which to schedule southbound through-trains.
So instead let us assume commuter trains run through, in which case we may as well assume they have good reliability so that they can be scheduled with 2-minute headways. Current peak traffic is 3 tph Brunswick, 2 tph Camden, 3 tph Penn, and lower combined traffic on the Virginia side. Assume that peak traffic will grow to 3 tph Brunswick and Camden and 6 tph combined Penn and through-HSR; in fact the most potential for growth is off-peak, and because multiple platforms are very long, long trains may be used if there are capacity problems.
We now have 6 tph terminating HSR, 6 tph through-traffic on the Penn Line (including HSR), and 6 tph through-commuter traffic on the Camden and Brunswick Lines; Camden and Brunswick are physically to the west of the Northeast Corridor, and so in addition to conflicts between terminating and through trains, we have conflicts between through-Camden/Brunswick and southbound through-Penn/HSR.
In this situation, we can have southbound terminating HSR and through-Penn/HSR trains clearing the throat at :00 and :02 again. Northbound terminating HSR trains have to depart 2 minutes after the arrival of southbound through-Penn/HSR trains, e.g. :04, and then northbound through-Camden/Brunswick trains can depart between :06 and :08; northbound through-Penn/HSR trains are always to the east of everything else and so do not conflict with anything.
Because southbound through-Camden/Brunswick trains conflict with terminating trains, they can be scheduled at the same time as northbound through-trains of some kind, which constrains the symmetry axis we choose but is otherwise workable. For example, if Camden/Brunswick trains both depart and arrive at :07 then with the terminating trains arriving :00 and departing :04, we have a symmetry axis ending in a 2 or a 7 (and through-Penn/HSR trains would arrive and depart at :02). But then the terminating trains also arrive just before the through-Penn/HSR trains and depart just after, implying they are slower or else there would be an overtake just north of the station. We can instead switch the trains – and then terminating trains arrive and depart :02, and through-Penn/HSR arrive southbound :00 and depart northbound :04. Note that there is no conflict between northbound terminating trains and southbound through-trains.
So it is possible to do this without extra infrastructure beside longer and level-boarding platforms, which are cheap. Let us finish by seeing what extra trains can be scheduled into the above 18 tph schedule. Scheduling 6 tph of terminating trains is easy: trains arriving :04 and departing :00, the opposite of the terminating HSR trains discussed above, will be adequately separated. The problem then is just the need to overtake the :02 through-trains along the tracks; however, at such a level of demand, 18 tph combined HSR and commuter on the Northeast Corridor, full four-tracking there would be necessary anyway.
But no extra through-traffic can be realistically scheduled into the same timetable, because the southbound :04 trains would conflict with the northbound :04 terminating trains. Changing the schedule so that it’s the terminating trains that arrive and depart at the same time is, however, possible: since we’re four-tracking the entire Baltimore-Washington line at this stage, we can have terminating trains arrive and depart :02, Camden/Brunswick trains do the same :07, and through-Penn/HSR trains arrive and depart :00 and :04. That said, this means it’s impossible to schedule more than 6 terminating tph into Union Station; I believe it’ll be easier to fill all those extra intercity trains into Washington than fill 18 tph going from Washington toward Virginia, both intercity and commuter.
Of course, the traffic levels discussed here are all very high, especially for HSR. An HSR system that fills even 6 tph is one that can pay for future capacity increases out of operating profits. The importance should be getting a starter system with reasonable capacity for the next few years and then build capacity projects as required, with immediate construction done only on the most critical segments or those that would be hard to reconstruct with more future traffic.
So we’re back to the question of what needs to be done with Union Station, and the answer is hardly anything. It’s not even Moynihan Station, which is also sold as a bigger transportation benefit than it is, but is at least billed as a grand station to be named after a politician more than anything (and is only about $1.5 billion). It’s even worse than Gateway and the Market East station, which would have positive transportation value, and are just very cost-ineffective. It’s not solving any problem for the foreseeable future; it’s just using big numbers about current traffic and growth to scare people into thinking more capacity is needed, and mostly it’s using small increases in track capacity to justify throwing billions of dollars on beautifying Amtrak’s headquarters.