My old Sante Fe engine quit, so I bought 3 NOS ones on line. One is the F7 style with the heavy chassis, but has no rubber wheels. The other ones are like my old one, and have rubber wheels. The new one just sits and spins the wheels with no cars connected. I don]t get it. He offered to send me another new one of the same style, but has no rubber wheels either. I don't understand how they run if they cannot get traction. The other two new ones run great.
Simple solution. Check the wheels for a groove that the rubber tire fits into. If no groove, most probably only one truck is working. A few in the past have had an issue with diesels as only one truck was working. A drive shaft fell off one truck.
Not familiar with exactly what loco you have. I am assuming Bachmann locos.
Pull the shell and check out the inside. Some older locos had only a motor one one truck.
No idea on how old your loco really is. Sometimes posting a photo will help a lot.
Rich
rubber tires are not usually a good idea. a decent locomotive will not need them for traction, an they are a known source of erratic operation and derailments.