You still see them in stores during the Christmas holiday, wending their way on tabletops through snow-laden model towns. But electric trains, and especially the locomotives that power them, require tons of loving care and maintenance as they get older.
Place your locomotive on a white, lint-free towel. Working on a white surface makes it easier for you to find a part or screw if you drop them.
Remove the body of the locomotive slowly and carefully using a screwdriver, and set it aside.
Check all parts of the locomotive for rust, oil clumping, dirt and loose parts using a magnifying glass or goggles.
Look for oil clumps or fibers that could be binding or locking wheels in place. If fibers are found, use tweezers to unravel them.
Use a cotton swab and solvent to remove any oil clumps, being very careful not to overuse or spill the solvent.
Wipe away the grime and grit using a cotton swab, and dab the cleaned pieces with a towel to dry them.
Apply oil to any pieces and joints that require it. Use a tooth pick with the tip just dipped in oil, and apply around all contact surfaces inside the locomotive.
Do not try to not repair broken pieces unless you have knowledge of machining. Check the classified ads in model railroading magazines to purchase the parts you need.
Repair bent parts by using pliers to bend them back. This may not fix the problem, so be prepared to purchase and replace the parts.
Reassemble the body and screw it back firmly.