6-1285 appears to be the number of a Lionel Set from 1972 that came with a Santa Fe AB locomotive.
The locomotive in that set is a #8020, which should only have one motor, and does have tire traction.
The number should appear on the side of the locomotive
The "A" unit has one motor, and a place for the engineer, with a windshield, and a headlight.
The "B" unit is a dummy, it does not have a motor, and looks like a rectangular box, no headlight or windshield.
I do not know how to post a picture here.
While 6-1285 was a freight set, an 8020 should have no trouble pulling three modern era 027 passenger cars. What are the car numbers?
If they are 027 cars, I would suspect the traction tires.