[KJKingJ]

> Note: this is not a great idea; trains release less than a third as much co2 as a truck and electrifying cross country rail would be very expensive. You need extremely high voltage for long distance transmission, which is incompatible with pantographs (the metal things that power trains/buses from overhead).

> You'd essentially need to build dedicated HVDC lines alongside all trunk routes, with regular substations (which are immensely expensive for HVDC) to inject power into the lines. Cross country HVDC would be really great for the grid, but it would be better to build a dedicated solution and forget about the trains. For context, the transmission losses for electricity cause ~2x more CO2 than all trains.

You're not wrong that electrification has a significant upfront cost associated with it, but using DC for it is absolutely not the preferred method for good reasons. Most rail electrification across the world uses 25kV AC overheads, which needs feeder stations typically only every ~50Km. Newer installations are moving to an autotransformer system, where transmission is at 50 kV AC but the trains still receive 25 kV AC, which reduces losses even further and increases the distance between feeder stations to every ~100Km.

Additionally, electrification means that the benefits of moving generation towards less environmentally impacting sources has an immediate benefit on the trains, rather than waiting until the train is replaced. In the UK, over the last year CO2 emissions per passenger per mile have dropped by 10% in just the last year [0] due to a combination of electricity generation moving towards more renewable sources and newly electrified routes.

[0]: https://dataportal.orr.gov.uk/media/1531/rail-emissions-2018...

[hwillis]

I was talking specifically about using nuclear to electrify transcontinental lines in the US. Those routes have sections hundreds of kilometers long that are basically desolate.