not sure if you have an actual set, but the train appears to be led by a (994) locomotive which is usually found in sets with the (941) 7" tender and the larger 7" cars. this was also the locomotive painted up for the Disney sets. in red you'd have an exceptional find, but in basic black and unnumbered, it is the most common version.
you have a (951) wedge tender, but please turn it around. some Marx tenders are tough to figure out, but when you see coal, chances are it should be facing forward.
the rest of the train is three pretty common 6" tin cars.
if you want to check out the motor, you can wind it by rolling it backwards. keys in these motors can be made from square bar stock, but frankly a small screwdriver will usually do the job in a pinch.
good luck with it.
cheers...gary
