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"Trucks have to use 17-22 speed transmissions and so they are at their maximum efficiency only a fraction of the time during acceleration."
With such narrow ratios, they stay much closer to the ideal RPM than cars, and very close to the top of the rather flat efficiency curve. In the lower gears, they are storing energy as kinetic or gravitational. I wish MPG guages would account for that.
RR cars are stressed to take the "buffing loads" that occur when two strings of cars are joined together in the freight yards. This makes them relatively heavy, although it works out OK on bulk carriers for iron ore, which may be the figure quoted. I'm sure that nobody claimed the RR could move one ton at a time at that rate, but for well-packed containers, it seems quite reasonable. We could probably engineer small robot trains that could get get that kind of efficiency on truck sized loads, too. The challenge might be in gracefully transitioning from roads to rails. Drivers might drop off trailers for a robot to forward to the proper station for pick-up, or ride along and catch some zzs.
Traditionally, trains have run at wide separations for safety, but with computers and such, they could be made up or broken up on the fly, with cars able to depart or join at any station without stopping the main train. An express shipment might be introduced at any point, but would not get the benefit of drafting, unless it collected a train of its own, which it probably would at busy times. With computers and robots handling the coupling of cars, and self-propulsion/braking, they could be built as lightly as the load dictated. Use of the rubber tires to lift the steel wheels from the track would be a simple way to eliminate all switching of the rails, which would be a problem area, and return the vehicle to regular road use.
I'm sure we could look up the payload ratio of railway cars and average trains.
Re: Donner Pass. Long, long ago, I rode my touring bicycle over that road, and stopped at the summit for a breather and a last look back. I was about ready to head out when I saw and heard a train coming up too. So I waited until the locomotive was abreast before starting. It still had a lot of train to get up to the summit and accelerate, so it took a loooong time to pass. :-) Carrying all my gear, I felt a certain kinship with the big freighter.
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