MTH or Lionel smoke unit in Atlas RS3?

Your first consideration will be to see if you can fit either of them in where the smoke unit needs to be!  Truthfully, I think that will be the biggest challenge.

I can always count on GRJ to offer great advice! Thanks!

Sounds like you’re saying that either unit could work fine if I can get them to fit… guess it’s time to pop the shell and see what I have for real estate…

You have a TMCC board unless it's a brand new Atlas, so it'll support diesel smoke.  The issue is indeed getting the smoke unit in place, I'd probably be looking as something like one of the American Flyer smoke units on Lionel, they're small.

The last run of the RS3’s had smoke. But they also added ERR cruise. Pretty sure the earlier runs used a TAS board. Upgrades aren’t my thing. But the TAS board takes up a fair amount of space. Adding cruise isn’t as economical as it once was. You could try contacting Atlas. I looked at the parts diagrams but they didn’t show there latest RS3.

This is what I’m working with…

It’s a conventional board with horn/bell. No support for smoke that I can see… There should be room for a smoke unit if I move the circuit board back into the cab area.

I think I’m going to do some research on Atlas’ parts site before I go too much further… EDIT- the RS3 doesn’t exist at all on Atlas’ site.

Honestly I’m not sure how far I want to go with this… the idea of just putting a smoke unit in that I already have in the parts bin is intriguing, but the more I think about what it would take to get the plumbing from the unit to the stack the more complicated it seems to get…

Some googling brought a little more information to light from “the archives”…

Apparently the TMCC models had smoke. Not sure if that applies to all TMCC models or just the 2012 run… but my unit is in the 2012 run, so the TMCC version would have had smoke. Of course the parts link is a dead end, but a google search for “Atlas O smoke unit” gave this result:

(two screenshots because I had to scroll down to show the description)

A vague description, and no ties to any specific locomotive, but I wonder if it might be the best starting point?

Again, the positioning of the electronics inside the shell will determine how much work it is to install the smoke unit.  Obviously, you have one that didn't come with smoke, so the first step is to see what kind of room you have.

I’m pretty sure I can move the reverse board closer to the cab end (looks like I could even use existing mounting holes) which should make enough room in the long hood for the smoke unit. They don’t give any size info in the listing for the Atlas unit but judging by the size of the electrical components in the picture it looks pretty compact.

I think either smoke unit that I have in the parts bin would fit too, but I’m assuming I would need some sort of rectifier/regulator to run either one…

Any unit would require some sort of tubing to connect it to the exhaust stack since the stack is off-center on the body…