There’s an excellent Uday Schultz blog post (but I repeat myself) about subway scheduling in New York. He details some stunning incompetence, coming from the process used to schedule special service during maintenance (at this point, covering the entirety of the weekend period but also some of the weekday off-peak). Some of the schedules are physically impossible – trains are scheduled to overtake other trains on the same track, and at one point four trains are timetabled on the same track. Uday blames this on a combination of outdated software, low maintenance productivity, aggressive slowdowns near work zones, and an understaffed planning department.
Of these, the most important issue is maintenance productivity. Uday’s written about this issue in the past and it’s a big topic, of similar magnitude to the Transit Costs Project’s comparison of expansion costs. But for a fixed level of maintenance productivity, there are still going to be diversions, called general orders or GOs in New York, and operations planning needs to schedule for them. How can this be done better?
The issue of office productivity
Uday lists problems that are specific to scheduling, such as outdated software. But the software is being updated, it just happens to be near the end of the cycle for the current version.
More ominous is the shrinking size of ops planning: in 2016 it had a paper size of 400 with 377 positions actually filled, and by 2021 this fell to 350 paper positions and 284 actually filled ones. Hiring in the American public sector has always been a challenge, and all of the following problems have hit it hard:
- HR moves extraordinarily slowly, measured in months, sometimes years.
- Politicians and their appointees, under pressure to reduce the budget, do so stupidly, imposing blanket hiring freezes even if some departments are understaffed; those politicians universally lack the competence to know which positions are truly necessary and where three people do the job of one.
- The above two issues interact to produce soft hiring freezes: there’s no hiring freeze announced, but management drags the process in order to discourage people from applying.
- Pay is uncompetitive whenever unemployment is low – the compensation per employee is not too far from private-sector norms, but much of it is locked in pensions that vest after 25 years, which is not the time horizon most new hires think in.
- The combination of all the above encourages a time clock managerial culture in which people do not try to rock the boat (because then they will be noticed and may be fired – lifetime employment is an informal and not a formal promise) and advancement is slow, and this too deters junior applicants with ambition.
Scheduling productivity is low, but going from 377 to 284 people in ops planning has not come from productivity enhancements that made 93 workers redundant. To the contrary, as Uday explains, the workload has increased, because the maintenance slowdowns have hit a tipping point in which it’s no longer enough to schedule express trains on local train time; with further slowdowns, trains miss their slots at key merge points with other lines, and this creates cascading delays.
Deinterlining and schedule complexity
One of the benefits of deinterlining is that it reduces the workload for ops planning. There are others, all pertaining to the schedule, such as reliability and capacity, but in this context, what matters is that it’s easier to plan. If there’s a GO slowing down the F train, the current system has to consider how the F interacts with every other lettered route except the L, but a deinterlined system would only have to consider the F and trains on the same trunk.
This in turn has implications for how to do deinterlining. The most urgent deinterlining in New York is at DeKalb Avenue in Brooklyn, where to the north the B and D share two tracks (to Sixth Avenue) and the N and Q share two tracks (to Broadway), and to the south the B and Q share tracks (to Coney Island via Brighton) and the D and N share tracks (to Coney Island via Fourth Avenue Express). The junction is so slow that trains lose two minutes just waiting for the merge point to clear, and a camera has to be set up pointing at the trains to help dispatch. There are two ways of deinterlining this system: the Sixth Avenue trains can go via Brighton and Broadway trains via Fourth Avenue, or the other way around. There are pros and cons either way, but the issue of service changes implies that Broadway should be paired with Fourth Avenue, switching the Q and D while leaving the B and N as they are. The reason is that the Fourth Avenue local tracks carry the R, which then runs local along Broadway in Manhattan; if it’s expected that service changes put the express trains on local tracks often, then it’s best to set the system up in a way that local and express pairings are consistent, to ensure there’s no interlining even during service changes.
This should also include a more consistent clockface timetable for all lines. Present-day timetabling practice in New York is to fine-tune each numbered and lettered service’s frequency at all times of day based on crowding at the peak point. It creates awkward situations in which the 4 train may run every 4.5 minutes and the 5, with which it shares track most of the way, runs every 5.5, so that they cannot perfectly alternate and sometimes two 4s follow in succession. This setup has many drawbacks when it comes to reliability, and the resulting schedule is so irregular that it visibly does not produce the intended crowding. Until 2010 the guideline was that off-peak, every train should be occupied to seated capacity at the most crowded point and since 2010 it has been 125% of seated capacity; subway riders know how in practice it’s frequently worse than this even when it shouldn’t be, because the timetables aren’t regular enough. As far as is relevant for scheduling, though, it’s also easier to set up a working clockface schedule guaranteeing that trains do not conflict at merge points than to fine-tune many different services.
Deinterlining and delocalization of institutional knowledge
Uday talks about New York-specific institutional knowledge that is lost whenever departments are understaffed. There are so many unique aspects of the subway that it’s hard to rely on scheduling cultures that come from elsewhere or hire experienced schedulers from other cities.
There is a solution to this, which is to delocalize knowledge. If New York does something one way, and peers in the US and abroad do it another way, New York should figure out how to delocalize so that it can rely on rest-of-world knowledge more readily. Local uniqueness works when you’re at the top of the world, but the subway has high operating costs and poor planning and operations productivity and therefore its assumption should be that its unique features are in fact bugs.
Deinterlining happens to achieve this. If the subway lines are operated as separate systems, then it’s easier to use the scheduling tools that work for places with a high degree of separation between lines, like Boston or Paris or to a large extent London and Berlin. This also has implications for what capital work is to be done, always in the direction of streamlining the system to be more normal, so that it can cover declining employee numbers with more experienced hires from elsewhere.