In addition to the wider than prototype bodies a more noticeable deviation from prototype on most RS1/RS3/ models is the way handrail posts mount to the walks. They should be top mounted to the walks - not mounted to the sides (like on the photos of the Weaver RS3 and AtlasO RS1 earlier in this thread). Early production Weaver RS3's had top mounted plastic handrails and apparently for reason of durability later versions were side mounted. For those wanting to improve the appearance of their ALCo road switchers you may want to consider installing a set of very nice Bowser/CalScale ALC0 lost wax brass handrail posts.
Ed, I did replace the OEM plastic handrails/posts with P&D brass posts on my Weaver model, but the pin on the bottom of the posts is a bigger diameter than the plastic pin. I had to drill out the existing holes and a couple of them broke thru the side of the body. I managed to super glue them in, cleaned up and painted they're hardly noticeable. Are the Bowser post pins smaller diameter?
Hi Bob - I can't answer your question as to the pin diameter of the Bowser/CalScale ALCo handrail posts as I no longer own the Weaver RS-3.. I purchased the RS-3 used at the Strasburg O scale show several years ago, and the brass posts were already installed. I don't know what the modeler did to install them. I do know they fit nicely in the holes and none of them broke through the side of the walks.
Many years ago Kemtron offered a brass RS-3 kit with lost wax brass handrail posts. It could be possible that the P&D posts came from those masters. In O scale castings have a mysterious way of moving from builder to builder.
Thanks Ed.
I like the chain drive of the Weaver RS3, I guess I'm more mesmerized by mechanical things than electronics 
although my engine also has the BlueRail board and internal battery, so maybe I like them both 
