Working on an emergency timetable for regional rail has made it clear how an environment of austerity requires tradeoffs that reduce efficiency. I already talked about how the Swiss electronics before concrete slogan is not about not spending money but about spending a fixed amount of money intelligently; but now I have a concrete example for how optimizing organization runs into difficulties when there is no investment in either electronics or concrete. It’s still possible to create value out of such a system, but there will be seams, and fixing the seams requires some money.
Boston regional rail
The background to the Boston regional rail schedule is that corona destroyed ridership. In December of 2020, the counts showed ridership was down by about an order of magnitude over pre-crisis levels. American commuter rail is largely a vehicle for suburban white-collar commuters who work in city center 9 to 5; the busiest line in the Boston area, the Providence Line, ran 4 trains per hour at rush hour in the peak direction but had 2- and 2.5-hour service gaps in the reverse-peak and in midday and on weekends. Right now, the system is on a reduced emergency timetable, generally with 2-hour intervals, and the trains are empty.
But as Americans get vaccinated there are plans to restore some service. How much service is to run is up in the air, as is how it’s to be structured. Those plans may include flattening the peak and going to a clockface schedule, aiming to start moving the system away from traditional peak-focused timetables toward all-day service, albeit not at amazing frequency due to budget limits.
The plan I’ve been involved with is to figure out how to give most lines hourly service; a few low-ridership lines may be pruned, and the innermost lines, like Fairmount, get extra service, getting more frequency than they had before. The reasoning is that the frequency that counts as freedom is inversely proportional to trip length – shorter trips need more frequency and shorter headways, so even in an environment of austerity, the Fairmount Line should get a train every 15 or 20 minutes.
In an environment of austerity, every resource counts. We were discussing individual trains, trying to figure out what the best use for the 30th, the 35th, the 40th trainset to run in regular service is. In all cases, the point is to maximize the time a train spends moving and minimize the time it spends collecting dust at a terminal. However, this leads to conflict among the following competing constraints:
- At outer terminals like Worcester and Lowell, it is desirable that the train should have a timed transfer with the local buses.
- At the inner terminals, that is South and North Stations, it is desirable that all trains arrive and depart around the same time (“pulse“), to facilitate diagonal transfers, such as from Fitchburg to Salem or from Worcester to Brockton.
- Some lines have long single-track segments; the most frustrating is the Worcester Line, which is in theory double-track the entire way but in practice single-track through Newton, where only the nominally-westbound track has platforms.
- The lines should run hourly, so ideally the one-way trip time should be 50 minutes or possibly 80 minutes, with a 10-minute turnaround.
Unfortunately, it is not possible to satisfy all constraints at once. In an environment with some avenues for investment, it’s possible to double-track single-track bottlenecks, as the MBTA is already planning to do for Newton in the medium run. It’s also possible to speed up lines on the “run as fast as necessary” principle to ensure the trips between knots take an integer or half-integer multiple of the headway; in our higher-investment regional rail plan for Worcester, this is the case, and all transfers and overtakes are tight. However, in a no-investment environment, something has to give. The Worcester Line is 90 minutes end-to-end all-local, and the single-track section is between around 15 and 30 minutes out of South Station, which means it is not possible to conveniently pulse either at South Station with the other commuter lines or at Worcester with the buses. But thankfully, the length of the single-track segment between the crossovers is just barely enough to allow bidirectional local service every 30 minutes.
No-investment and low-investment plans are great for highlighting what the most pressing investment needs are. In general Boston needs electrification and high platforms everywhere, as do all other North American commuter lines; it is unfortunate that not a single system has both everywhere, as SEPTA is the only all-electric system and the LIRR (and sort of Metro-North) is the only all-high-platform system. However, more specifically, there are valuable targets for early investment, based on where the seams in the system are.
In the case of integrated timetabling, it’s really useful to be able to make strategic investments, including sometimes in concrete. They should always be based on a publicly-communicated target timetable, in which all the operational constraints are optimized and resolved for the maximum benefit of passengers. For example, in the TransitMatters Regional Rail plan, the timed transfers at the Boston end are dealt with by increasing frequency on the trunk lines to every 15 minutes, at which point the average untimed transfer is about as good as a timed hourly transfer in a 10-minute turnaround; this is based on expected ridership growth as higher frequency and the increase in speed from electrification and high platforms both reduce door-to-door trip times.
The upshot is that austerity is not good for efficiency. Cutting to grow is difficult, because there are always little seams that require money to fix, even at agencies where overall spending is too high rather than too low. Sometimes the timetables are such that a speedup really is needed: Switzerland’s maxim on speed is to run as fast as necessary, not as fast as trains ran 50 years ago with no further improvement. This in turn requires investment – investment that regularly happens when public transportation is run well enough to command public trust.