A regrettable feature of rail transport is that often, the speed of a line deteriorates over time after it opens or finishes a major upgrade. This can come from deferred maintenance or from proper maintenance that includes stricter speed limits or more timetable padding; in either case, it’s because maintaining the original schedule is not seen as a priority, and thus over time service degrades. In some cases, this can also include a deterioration of frequency over time, usually due to inattention.
This is not excusable behavior. The networks where this feature exists, including the US, France, and Germany, are not better-run than the Shinkansen, where I have not seen any such deterioration of Shinkansen speed in many years of poking around timetables on Hyperdia, or the system in Switzerland. Switzerland’s timed transfers make it impossible for gradual deterioration of speed to accumulate – trains are scheduled to just make connections to other trains at major nodes, and so if they slow down too much then they can’t make the transfers and the entire network degrades.
I wish I could say degradation is a purely American phenomenon. It’s very common in the United States, certainly – on the subway in New York the deterioration made citywide news in 2017 (including one piece by me), on the trains between New York and New Haven the schedule is visibly slower now than it was in the late 2000s, on Amtrak the Northeast Corridor has degraded since the 2000s. Speed is not viewed as a priority in the US, and so there are always little excuses that add up, whether they’re flagging, the never ending State of Good Repair program on the New Haven Line under which at no point in the last 20-25 years have all four tracks been in service at the same time, or just inattention to reliability.
But no. France and Germany have had this as well. The TGV used to run between Paris and Marseille in 3:03 every two hours and in 3:06 every other hour; today I see a 3:04 itinerary every four hours and the rest start at 3:11. And here, the Berlin-Hamburg trains were timetabled at 1:30 in the mid-2000s, giving an average speed of 189 km/h, the highest in Germany even though the top speed is only 230 and not 300; the fastest itinerary I can find right now is 1:43, averaging only 165 km/h.
I stress that such deterioration does not have any benefits. It’s an illusory tradeoff. When New York chose to slow down the L trains’ braking rate as part of CBTC installation, this was not seen in reduced systemwide maintenance costs; speed just wasn’t a priority, so the brakes were derated. The 7 train, as I understand it, will instead speed up when CBTC comes online, a decision made under Andy Byford’s program to speed up service.
Nor has France saved anything out of the incremental slowdowns in TGV service. Operating costs are up, not down. The savings from slowdowns are on the illusory to microscopic spectrum, always trumped by increases in cost from other sources, for example the large increases in wages in the 2010s due to the cheminot strikes.
By far the greatest cost of speed is during construction. During operations, faster service means lower crew costs per km. This is where the Swiss maxim of running trains as fast as necessary comes from. This isn’t about derating trains’ acceleration – on the contrary, Switzerland procures high-performance trains. It’s about building the least amount of physical infrastructure required to maintain a desired timetable, and once the infrastructure is built, running that timetable.