Ancient battery-electric shunter, the battery long since disappeared. The owner assured me it was working last time out (which was probably when we still had a King).
Quite interesting construction, it has a big 12 volt motor in the cab with a large flywheel coupled to the wheels with a brake in the cab working on the rim of the flywheel. All manner of knobs and levers work the electrical apparatus housed in the cab, any part of which looks like it would give the HSE man a fit.
Pushes along smoothly although with effort as you are, effectively, spooling up the flywheel and motor. I guess it weighs about 40 pounds without a battery.
Length 26 inches