S2's, S4's, and the B&M 1271---Question

Model Railroader General Discussion (Model Railroader)
1

Hello All.

I’ve developed a very fond liking for the B&M 1271, an S Unit.

Here is a pic I found on NERail:
http://photos.nerail.org/showpic/?00000027.jpg:bysearch:1271:SEARCHTYPE=SIMPLE&PAGE=1&SEARCHSTRING=1271&BOOL=ALL

From different sources I have seen that this loco might be an S2 or an S4.

The BMRRHS archives say that it is an S2. However, in that archive I don’t see any listings for S3’s or S4’s, which they defenitley had.

Diesel Victory Publication by Classic Trains said it is an S4, as does the description of the picture.

With this, would anyone be able to tell me from the locomotives features what it is? I’ve heard that S2’s and S4’s have the same trucks. Is that correct?

If it is an S4, how close are S2’s and S4’s? Would an S2 fool the eye for a model? What details might I need to add/change for an S4 from an S2.

I’m sorry for all the questions, any help is appreciated.

Thanks

2

railroadyoshi,

I think this would actually be better posted on the Prototype forum.

To answer your question, the trucks were the difference between the S2s and S4s, as well as the S1s and S3s switchers. I think only a true rivot counter or S diesel fan would even notice the difference. Here’s a helpful link for you:

http://yardlimit.railfan.net/alco/spotting/index.html

After viewing the trucks in the pic, it’s definitely an S4. I have a Proto 2000 S1 on my layout and it’s probably my favorite locomotive. I’ve really developed a real fondness for these switchers myself.

Tom

3

I think this is a similar case to my question a long time ago about RS-10’s and RS-18’s which are virtually identical in every way except horsepower…which is not tangibly visible.

Trevor

4

Thanks so much!
That explains everything.