Interchangeability of Weaver RS shells

If it were me I would contact Northwest Short Line for parts and leave it as a single motored unit. Mine runs (converted from 3 to 2 rail) most beautifully. 

Mark in Oregon

Do a search here for rs-3 weaver repairs and you will see they had a bad batch of plastic parts from the factory. Once the bad gears are replaced they make good runners. I have 5 engines and 4 needed the upper gear replaced and several wheel sets had cracked gears too. I used P&D for replacement parts. 

The single motor drive was the "standard" weaver drive for years.   It is a wonderful drive and is easy to repair.   Great speed control and great low speed performance.    I have a fleet of FA2s and RS3s.   

The two motor drives are newer.   At some point they converted to the two motor drives in the US built engines which are the RS3, FA2 and GP38-2.   

I believe the screw spacing is different on the 2 motor chassis which are just stamped steel plates in place of the detailed plastic chassis.    But the shell should fit over and you could drill new holes in the steel chassis for the old screw mounts.

Be careful with the screws into the plastic shell.    I recommend DO NOT use a power driver on them at all.   Gently put the screws in by hand.   I turn the screws gently in the wrong direction until I feel/hear a click which means the screw found the original threads in the shell.   I think tighten it down finger tight.

The Weaver RS3 body itself will screw off the walkway/handrails part. You can swap the shells this way from the old single motor to the new vertical twin motor however you may have to paint the walkway piece to match your shell unless you have two of the same roadnames/colors bodies.