It's an initial step. I'm not sure if the technology would work for their main routes, but this at least is a step to test and evaluate how this technology works.
Electrifying US rail outside of switchyards won’t ever be practical, unless you could drive down the cost of electrified tracks with a third rail (overhead electric at this scale would be obscenely expensive).
* Double stack well cars sit very low. There are currently no third rail installations in the US that wouldn't get sideswiped by a well car. So their installation would basically mean forgoing half of freight revenue.
* Third rails have to operate at lower voltages due to the fairly small clearance to the ground, and so they require more frequent substations than higher voltage overhead wires.
Edit: excellent resources, thanks all for replying.
Which is why third rail systems are usually only seen in metro lines and similar. I'd guess in urban environments sprinkling more substations around isn't such a huge issue, as access to the power grid is seldom an issue. Also metro trains need much less power than a high speed passenger train or a heavy freight train.
generally speaking, third rail allows for a smaller tunnel diameter than overhead systems. (third rail is located near the wider section of tunnel in the middle whereas overhead requires extending the height.)
Anyone building new tunnel should allow the little extra room for overhead, but retrofitting may not be worth it.
This would probably be the way to go if the US would introduce electrified rail routes.
An overview of Third rail vs. Overhead Wire from a transit perspective, but it's similar with freight https://www.youtube.com/watch?v=LGI9XuHE3P0
TLDR:
Grade crossings are more complicated, if not impossible
Smaller voltage since it's closer to the ground and the grounded rails.
Thus higher current & more losses, needing more power stations.
This is probably way worse for freight, since it weighs more and there are long gaps between civilization on the routes.
The other big problem (in addition to the ones you've outlined) is that having miles of live conductor at ground level isn't particularly safe - for track crew, trespassers, or wildlife.
Britain has essentially stopped installing third rail for all these reasons. It's all 25kV overhead now.
And the same issue also applies to every instance of pointwork.
Why is that? Russia, a considerably poorer country beset by endemic corruption and other major issues, has managed to electrify the 9000+ km (considerably longer than any coast to coast US railway route) Trans-Siberian railway. With overhead lines, obviously.
Personally, I would prefer electrified freight rail, I’m just unsure if the US knows how or can do it. I suggested third rail if the cost came down because in America, you can usually coax towards the right solution if you can show drastic cost savings/reductions (see the rapid renewables uptake as costs declined over the last decade). At a glance, it seems easier to throw down a third rail while doing track work versus the construction effort for thousands of miles of overhead gantries and 25kv power lines. You could pair this with HVDC transmission lines looking to use railroad right of ways to avoid NIMBYS (the SOO HVDC line in the Midwest, for example [4]), for power accessibility.
[1] https://www.nytimes.com/2021/11/28/us/infrastructure-megapro...
[2] https://www.nationalgeographic.com/science/article/mega-proj...
[3] https://www.vox.com/22534714/rail-roads-infrastructure-costs...
Texas Central also seems to be making progress on Dallas-Houston high speed rail.
That said, I agree that the taxpayers don't feel like giving billions of dollars to BNSF and Union Pacific, so they probably won't electrify until there is no other option. Fuel costs just aren't high enough to make it profitable, and the environmental externalities are still free. (But, of course, you'd rather see a 500 car freight train burning fossil fuels than 500 tractor trailers driving down the interstate burning fossil fuels.)
(There are lots of things working against CAHSR. The route has been chosen politically rather than to minimize SFO-LAX travel times. Given infinite budget, you travelers on that route don't want to go through Bakersfield, as it's out of the way. And, the SFO/LAX city pair is already not a particularly optimal pair, it is kind of reaching the high end of distances that make high-speed rail the best travel option. That's why I look at Texas Central and Brightline for models of what to do in the future. Texas Central is a really good city pairing, in a region where their 16 lane highways can't handle the traffic volume. But I temper my enthusiasm in that not a lot of construction work has been done; I can't find any updates newer than September 2021 when the CEO said pessimistically that there is only a 50/50 chance that construction will start in the next 6 months. We're near the end of those 6 months.)
Currently half of the work going on right now is grade separation that includes both the future high speed rail line and the current freight rail line. So there is some method to their madness. The grade separation provides immediate benefits.
Lot of info linked here https://www.buildhsr.com/
They don't need to be convinced to spend money. They are spending more than ever. But you're dead on about it all being crisis-driven now. Or maybe it always was? WWII was clearly that, then the cold war/space race, then Star Wars, then GWAT (or GWOT?) -- Global War Against/On Terrorism, and now Covid - Build Back Better. Crisis spending is perfect cover for pork and grift, because anyone who questions it can be painted as unpatriotic.
In any sufficiently big project, I'm coming around to the opinion that there's some amount of timeline that results in an effective "never".
I think it's just that at some point, people stop caring? Or at least feeling like they have any motivation to hustle?
And once that happens, the end result in lethargy and a grinding halt to actual progress. Even if checklist items seem to be getting ticked off.
But imagine a train that can go for a kilometre or two without power lines, because it's a hybrid. Suddenly every low bridge and most tunnels are handled by just lowering the pantograph (power pick-up) as you go under them. If lines cross in strange ways or go under buildings you just don't put power lines there. At level crossings you skip the power lines, so no tall trucks will hit them.
I think there are probably huge savings to be made by putting the power lines in the easiest places and bridging the rest with hybrid. The battery recharges at speed as soon as power returns. You can even install a small diesel motor on the locomotive that has enough power (with gearing?) to creep to the next overhead power line if the train is unexpectedly stranded.
When a power line is downed by a tree (or a cable thief), the cleanup crew just removes that section. It is put up later when the backlog from the storm has been cleared.
Of course you need the train to know its location and have an updated list of where to lower the pantograph. That seems to me like a totally solvable problem in 2022. It's like 100 times easier than a self-driving car or landing a rocket with retropropulsion.
India has electrified almost 50,000 kilometers of track with overhead wires and this is increasing eabout 5000 km a year. China has almost 100,000 km of electrified rail track.
So very likely whatever barriers to electrification there are in the US are largely self inflicted and maybe corruption or regulatory capture driven.