Convert is an important word there. It's very obviously not the first electric train service, but they're normally built as electric from the beginning.

> Convert is an important word there.

Yes, that's why it's misleading when the author is framing the important part as "electric train exists now" and not "electric train used to be non-electric". If one must nitpick, the biggest conversion west of the Mississippi River was probably the Milwaukee Road whose converted electrified main line dwarfed Caltrain's 51 miles: <https://en.wikipedia.org/wiki/Railroad_electrification_in_th...>

“The first division to be electrified was the Rocky Mountain Division from Harlowton, Montana to Avery, Idaho. This covered a distance of 438 miles (705 km) and began electric operation in 1917. The electrification remained in operation until 1974, when diesel locomotives took over.”

“The second division to be electrified was the Coast Division between Othello, Washington to Tacoma, and to Black River just south of Seattle. This covered a distance of 207 miles (333 km) and began electric operation in 1919. The electrification remained in operation until 1972, when diesel locomotives took over.”

tl;dr: solar, mostly

The short answer is that average generation in CA is:

- 51% solar

- 22% natural gas

- 21% other renewables (hydro + wind + geothermal)

- 6% nuclear

- 0.1% coal

sources:

- https://www.eia.gov/state/print.php?sid=CA

- https://www.gridinfo.com/california

- caiso.com is also good

The medium answer is that trains run during daylight hours, so they probably consume more solar and less natural gas than the averages suggest.

The long answer is that counterfactual modeling of electricity generation is surprisingly subtle. E.g., the Diablo Canyon nuclear power station is going to run regardless of whether Caltrain electrifies, and no more nuclear is being built either way, so really Caltrain is "responsible" for none of the nuclear generation in the state, even if the trains are consuming power at the same time that Diablo Canyon is generating. In this analysis frame, you tend to look at the marginal plant being built, which likely further pushes toward solar but depends on tons of factors in reality.

Neat. Thank you!

> What fuel is used to generate the electricity? (Honest question since I have no idea how electricity markets work)

Depends on which system you're talking about. Muni is 100% hydro. BART is more coy but claims their electricity is "greenhouse gas-free" and their diesel (for eBART) is "renewable".