HO S2

[lajry]

Not all the ALCO S-2/S-4s ended up w/ the from the factory stacks. Alot of eastern & western RRs made them taller & either cylindrical or rectangular. See the attachments:

   
   

Have many more pix of the different ALCO switcher stacks. Too many to put all here so PM me w/ your email addy if you want me to send them to you.
Wanting the right ones to run on my LAJ layout had both kinds (ATSF & LAJ) made by 3D printing. UP also had taller cylindrical stacks. Can use the LAJ one but will need to add a "weld" line or a band about 1/2 up the stack. Haven't seen any SP pix w/ non ALCO stacks. Check as many pix of your RRs ALCO switchers to see which kind of stacks that RR had. The RRs weren't always consistent about changing the stacks.