Yes... and no

The Atlas/Kato RS3 and RS11 are the same. The RS36 is not. More info at http://www.atlasrr.com/hoparts.htm

May/may not be important to

May/may not be important to you, but as I recall, seeing as the original Atlas/Kato frame is the same, this results in the Atlas/Kato RS-11 having a wheelbase that is nearly 1' too short.

Wasn't a huge issue to me "back when".  (i.e. Not bad enough to warrant the work needed to correct it.) Don't think it would be now... not for sure.

Andre

I think in yellow box days,

I think in yellow box days, the frames for the RS-3 and RS-11 were the same.  In the retooling that happened when production moved to China, the RS-11 frame was made properly, which also enabled accurate RS32-36 models.  I do know for sure that RSD trucks will fit the newer China frames under the RS32s.

c

The China frames have tabs on the ends for the couplers to screw into, much better than the yellow box method of body mounting.  Under a heavy load the older units would deflect.

Simple answer is yes.

RS 3 frame will fit under the RS11 body with a very slight mod to the coupler mount, put a chamfer on the topsides off the coupler casting to clear ribbing moulds on the under side of the pilot frame  and take a small amount off the front face of the casting as well. RS3 frames also need the small lugs on each side filing away. RS36 chassis is a straight swap but front weight will need to be swapped to get headlight at the right height. Same with the RS3 but lights are only a few millimeters to low so raise with blutac. Old Yellow box frames can be used under newer bodies but you will have to fabricate a coupler mounting pad.I've got 8 RS11/32/36 combinations using various  chassis from swaps. I think the next run of RS11's with sound will have a few differences to accommodate speaker housings. I was aware of the wheelbase issue and using an RS3 frame doesn't improve things, I just had several undecorated bodies and cheap Ebay RS36 purchase.