I suspect the issue is with the engines, not with having DCS running. Did you clean and lube the FA? You could have grease on the armature shaft worm gear that is literally hard, the commutator on the engine is likely dirty, too and both could cause what you saw, especially a dirty commutator. . If you search on here, or on you tube or the net, there is a ton of information about how to clean and lube PW equipment, it isn't hard.
With the steam engine, that is likely either the e-unit is stuck or it supports it the control arm is in the neutral position (the lever). Besides asking if the engine has been lubricated recently, with the e-unit I wouldn't use WD40, get yourself a can of tuner cleaner , which both cleans and lubricates, and try squirting that on the e-unit to clean the drums and fingers.
