A train consist of just an engine and a cabin car is a "caboose hop". Here it is 1920 on the Pennsylvania Lines. The engine is an H10s 2-8-0 and the cabin is a class NE bobber. A program is underway to rebuild P.L. bobbers into 8 wheel cabins with steel underframes, making them compliant with state's laws. Old class NB, NC, NE and NEa are being made into class N6a and N6b by adding some length to the old bodies to fit their new underframes.