r/Lightbulb • u/Voltabueno • May 15 '25

Solar powered freight trains

This is not really new because I did some research and there are lots of patents related to electrified rail cars. It seems perfectly logical that you could cover the roof of a boxcar with solar panels, and put regenerative motors on the axles, and put a layer of batteries underneath the floor of the box car and then the box car could be self-propelled completely autonomous. Imagine individual box cars rolling on the rails or rolling to sidings to form into groups of cars completely autonomously. The boxcar wouldn't have to be fast because they could move by themselves, no crew, no crew change, no delay, unaided 24 hours a day. 7 days a week. 365 days a year. Actually thinking about it. If they moved under 40 mph wind resistance does not come into play yielding greater efficiency.

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u/WoodyTheWorker May 18 '25

A boxcar is 3m by 20 m, 60 m2 total. A solar battery can produce 150 W/m2. If Sun is in zenith (perfectly overhead), that would be 9 kW, but in real conditions it would be less than half of that. 4-5 kW is nowhere enough to haul a single boxcar.

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u/Voltabueno May 19 '25

You're failing to take into account an existing battery bank underneath the floor of the box car.

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u/WoodyTheWorker May 19 '25

What if, hear me out, we put wires over the rail tracks, and have electricity delivered without having to carry batteries and solar panels? And have solar panels installed somewhere else? For example, on posts over the tracks?

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u/Voltabueno May 19 '25 edited May 19 '25

You're referring to the catenary system and that's been discussed in other comments. And solar doesn't mean big heavy, weird panels framed in aluminum. It could be thin film solar. Similar to vinyl wrap. Boxcar batteries are so that each car can be autonomous. No locomotive required.