So, the way Rick arched the panel was quite clever, gives it exposure in varying positions.
But clearly, it reduces the maximum power, a good approximation would be under half, and probably even 1/3 capacity even in optimal conditions.
So now you have 100 ma at 19.6 best case so under 2 watts. So maybe in perfect conditions you could run an LGB loco with no cars on that, but now you have to pull 3 cars for 1/2 motor unloaded… basically you will probably agree that loading the loco down, and sunlight not always being the best, 5 cars would be a good estimate, 500 ma tops at 19.6 and need to factor in the conversion loss (using a DC to DC converter, which are easy to procure.
So a train that runs only in full and bright sunlight, go into the shadow and the train stops.
If I was determined to build one, I would double the power to compensate for issues, and now you are at 10 cars…
Anyway, it’s fun to think about, but as I said before, just one car with a battery would be enough.
Greg