How do you safely remove a Spectrum 2-10-2 and a 4-8-2 cab so as not to damage the models? I have a Precision Scale CNR cab that would look great on these two locomotives.

I am having a great deal of frustration with my second 4-8-2 made by Spectrum. The first 4-8-2  I bought form a discount hobby shop on Ebay made a very loud whining sound and did not rum properly. The seller gladly accepted the unit back for an exchange with another factory sealed unit. This one sits on the track - the motor hums but does not move. The headlight has also stopped working. Am  I doing something wrong? This one does not make the damaging sound that the first unit made. My other Spectrum staemers run great - 0-60, 2-8-0 and a 2-10-2. The layout is DC with all units running with plugs in the circuit boards if they need them. HELP!

This may be a very silly question, but is it really just a matter of unplugging one and plugging in another? I would like to change the 4-8-2 RF&P long USRA tender to a VANDERBILT HICKEN TENDER. The smaller tender would be perfect for the engine style I have in mind and they are both Spectrum products. I should point out that I will not be running the locomotive with DCC but rather DC.