The Cost of EMU Maintenance

Caltrain recently published a strategic financial plan update, where we learn that maintaining each EMU in the new electric fleet in good working order is expected to cost $1.2 - 1.5 million per year, a significant increase from last year's estimate. This post seeks to answer the question: is that crazy?

This analysis revisits and updates an older post here.

Historical vehicle maintenance costs

Note these figures are in constant 2023 dollars

The National Transit Database is a fantastic resource provided by the federal government, charting facts and figures for every transit operator in the United States. For the period 2000 - 2022, we look up vehicle maintenance costs and vehicle revenue miles for Caltrain as well as for two regional rail operators in the New York City area (Metro-North and LIRR), who operate the largest "heavy rail" EMU fleets in the United States in a region with similarly high costs as the Bay Area. Note that New Jersey Transit is not included because teasing out their large bus fleet from the overall agency figures is complicated. Dividing vehicle maintenance expense (adjusted for inflation to 2023) by vehicle revenue miles, we get the approximate per-mile cost of vehicle maintenance. One can guess that Caltrain's increase after 2017 is related to operating the legacy fleet way past its retirement age. In constant 2023 dollars, eyeballing this chart, the cost of maintaining EMUs might be around five bucks per vehicle revenue mile -- let's charitably say four because Caltrain's fleet is brand new and won't break down as much as older fleet mixes used by the other operators.

Caltrain EMU vehicle revenue miles

The new service plan published by Caltrain makes it easy to calculate the number of annual EMU vehicle revenue miles. There are 66 trains per weekend day (33 in each direction, for 16 hours of half-hourly service, with every other train serving Tamien) and 104 trains per weekday (52 in each direction, with 18 hours of half-hourly service = 36 plus 8 hours of additional peak express service = 16). It's 46.7 miles from SF to SJ, and 48.4 miles from SF to Tamien. That adds up to 2*(16*48.4+17*46.7) =  3137 revenue train miles per weekend day, and 2*(18*48.4+18*46.7+16*46.7) = 4918 revenue train miles per weekday. Each train has seven vehicles, as defined by the FTA. Assuming each year has 6 holiday weekdays with weekend-like service, that all works up to 11.2 million vehicle revenue miles per year, which is... a lot. For context, the most service Caltrain ran pre-covid was 7.9 million vehicle revenue miles. The increase of 41% arises from running half-hourly service all day, every day, with long seven car trains.

Caltrain projected vehicle maintenance expenses

Note these figures are in year of expenditure

The 2024 strategic financial plan helpfully breaks out projected annual vehicle maintenance expense by fleet, with the EMUs charted separately from the diesels. The EMU costs are shown at right (MoE = Maintenance of Equipment). These figures are in year of expenditure, not inflation adjusted, so we need to make some assumptions before we can compare apples to apples. Taking 5% inflation and deflating these figures back to 2023, the previous forecast (in red) was $12M, while the new forecast (in blue) is closer to $21M with 19 EMUs climbing to $25M when all 23 currently on order are delivered. We can guess that in the out years, Caltrain is assuming that ridership has bounced back enough that the FTA will require them to operate six trains per peak hour per direction (104 + 32 = 136 trains per weekday) as originally planned, further increasing to 13.9 million vehicle revenue miles per year.

Putting it all together

We've made some assumptions that are not completely valid -- namely that vehicle maintenance cost scales directly with the number of revenue miles operated. To first order, this is true, but vehicle maintenance cost has time-based components (such as mandated inspections, or replacement of ultraviolet-crazed window glazing) and distance-based components (such as wheel and brake wear). Not everything scales proportionally to revenue miles. With this caveat in mind, let's see what happens.

If you multiply 11.2 million vehicle revenue miles by $4 of vehicle maintenance cost per vehicle revenue mile from the National Transit Database, you end up at $45M per year (again, with everything in 2023 dollars.)

Caltrain's latest figure is half that, so what looks like a large increase in their latest strategic financial plan may still be an underestimate. Their estimate of $21M divided by 11.2 million vehicle revenue miles gives just $1.90 of vehicle maintenance per vehicle revenue mile for the EMU fleet (in 2023 dollars), a value lower than Caltrain has ever achieved with its legacy fleet.

Seen another way, 11.2 million vehicle revenue miles operated with 19 trains works out to 590,000 vehicle revenue miles per year (or, since each train has 7 vehicles, 84,000 miles per year on the odometer) corresponding to $2.4M of vehicle maintenance cost per EMU set per year. Their estimate of $1.2 - 1.5M seems low in comparison. This could be due to high utilization, which would dilute the time-based component of maintenance cost.

Verdict: these EMU maintenance costs are not crazy -- they might even be too low.

Appendix: Gilroy branch

While we're at it, we can do a quick sanity check on the Gilroy branch, which will continue to operate with a reduced diesel fleet. There are four weekday round trips. Gilroy is 30 miles from SJ. The trains have five cars. This works out to 1200 vehicle revenue miles per weekday, or 306,000 vehicle revenue miles per year, or less than 3% of Caltrain's total. At four bucks a mile, that's $1.2M per year for the entire diesel fleet.

Caltrain's figures are closer to $7M per year (again, in 2023 dollars). That seems like a lot, but consider the extremely low utilization of the dedicated diesel fleet, less than 7000 miles per year per diesel locomotive, means that time-based vehicle maintenance costs will dominate, the opposite of the EMU fleet.

If the fiscal cliff is real and not some made-up crisis, then the under-utilized rail service on the Gilroy branch should be replaced by bus service and the entire diesel fleet that is dedicated to it, maintenance costs and all, should be unceremoniously dumped off Caltrain's balance sheet.