You could power idling locomotives with it. However, do note that the PS/1 locomotives will be making noise all the time they're "parked". Also, if you run with smoke, they'll be running the smoke units.
A better bet is to install BCR's in them, than no charging required.
If you're handy, you can make a supercap replacement for 9V batteries as well. Two matched 1.5F supercaps in series and a battery clip. I use heatshrink around the two caps when assembled. Note that the red lead goes to the negative side as you're creating a battery, not connecting to one, so the polarity of the battery clip is reversed.
