Complex sentence: James adopted the name George Formby in the late 1890s, supposedly because when he was sitting on the platform waiting for a train he saw a goods train on its way to Formby, a small Liverpool suburb.
Split into simpler sentences: James adopted the name George Formby in the late 1890s, supposedly because when he was waiting for a train. He was sitting on the platform when he saw a goods train on its way to Formby, a small Liverpool suburb.