The International 50T (twine) and 50W (wire) balers used the Farmall Cub C-60 engine rated at 16 HP. The International 45 baler used a Wisconsin TFD four cylinder air cooled engine. The International 55T (twine) and 55W (wire) balers used the Farmall Cub C-60 rated at 15 HP. I don't know why the engine was rated one horsepower less on the later bailers. The electric baler mentioned was a 45 with an electric motor and was shown at state fairs and such but I don't know if any were actually sold. I saw it in Memphis at the International Harvester exhibit at the Mid South Fair, probably in 1956.