There was once a train named Electro. Electro had a special way of travel that was unlike any other train. He did not ride on rails. He did not even ride on roads. Electro was unique because he was able to travel between the earth and the clouds on bolts of lightning. Every time a bolt of lightning struck, it would carry Electro down to earth or back up to the sky. Because he had so little time, Electro could only pull one car of protons at a time, but when big storms came through, he was able to carry lots and lots of loads.
Electro was also special because he did not need a coal car or even a diesel engine. Because lightning is full of energy, Electro simply pulled electricity out of the lightning through his magnetic wheels. This gave him the power and speed he needed to make it down to earth or back up into the sky.