BandA wrote: ↑Sun Jul 18, 2021 5:07 pmIs acceleration causing schedule-keeping problems for the T? How much time would be saved for a Worcester, a Fitchburg, or Providence train if they were electric push-pull or DMU or EMU?Acceleration is the main determinant of how fast commuter rail service is, not top speed. Most commuter services rarely hit MAS, and only for short segments. Thus, fast accelerating EMUs or loco-hauled electric with multiple locomotives will do a lot more than 125mph capable commuter equipment will. Faster commuter service would do little to cannibalize Amtrak Regional in most cases, they are two difference services, and two different markets. NHV-NYP is an exception, the new MN service will likely cannibalize some of the small amount of traffic on that route, but it's probably miniscule, as most already goes to GCT on MN.
CRail wrote: ↑Sun Jul 18, 2021 6:23 pmThere's no argument that electric powered vehicles aren't superior in efficiency and performance for service making frequent stops, the argument is over whether or not the benefits gained are worth the prohibitive infrastructure expense. I've opined repeatedly and maintain my position that electrics are a no brainer on some routes but don't make sense on others.For the T, everything except the Old Colony and Greenbush lines should be electrified. Part of the issue is excessive cost, which plagues all of our infrastructure. Lower maintenance, faster speeds, lower energy costs, and of course decarbonization are all huge benefits to electric, and are well worth the $2.4M/mi cost for overhead AC electrification. If you start to see figures significantly higher than that, then there are cost problems, and those need to be addressed as such.
BandA wrote: ↑Tue Jul 20, 2021 2:07 amI think batteries will remain impractical except for niches like filling in gaps under bridges, switching engines in covered coach yards, etc. Hydrogen has the fundamental problem that it has to be manufactured from something else, and burning something else is usually cheaper than burning a synthetic fuel.The idea is that Hydrogen will be produced by renewable energy, but we need to use it way more efficiently than we use diesel today, like with relatively lightweight HMUs on lower density routes. Batteries are not useful for commuter rail at their current energy density and weight, I could see them being useful for freight switching, and in fact such a system was used many decades ago on the Chicago North Shore Line for off-wire freight switching. There are plenty of small yard, terminal, and high density shortline operations where battery switchers would make sense.
Using batteries for going under bridges is rather problematic and the clearance issues should actually be dealt with, not kludged around. I could see mainline freight electrification using locomotives with limited battery range to get in and out of grain loop loaders or intermodal yards, but that's a whole different topic.
Switching to LNG or CNG isn't useful, it's switching one dirty fossil fuel for another.