Solar ditches make more sense. Carrying solar panes add weight and air resistance. The trailer area is 416 ft which can hold ~33 panels if panel configurations are optimized for a trailer. Weight will be 3000 lbs, which cuts the tare payload by 6%. This is not enough electricity to run a semi with two drivers splitting driving responsibilities, running day and night, and in weather that does not have power for the cells.

Trains are the most efficient system that we have. I wonder how the math would work for trains? I expect that it would be a net gain, but the added complexity of connecting and disconnecting for each car as the cars get switched in yards would be a nightmare. Once travelling, there is little braking and acceleration, which lowers the power demands.