ALCO RS-2 Build List

One of the articles that I have been working on for Shoreliner covers the DERS-2 locomotives (RS-2 and RS-3).  There is one specific piece of information I haven't been able to nail down, so I'm simultaneously hoping others may have a reference I don't, while sharing the list that I've compiled that  I don't think has been published anywhere in this form.

Of course, this is a work-in-progress, so may be in need of many corrections.

Alco Specification E-1661

When built, the RS-2 designation didn't exist yet. The first locomotives were built using Alco Specification E-1661. The RS-2 name wasn't applied until c1952, after production had evolved to the RS-3 (Specification E-1662).

Alco Specification E-1661A (and B)

In March of 1947, D&H 4006 (builder number 75141) was built under the new specification E-1661A, although CIL 22 (b/n 75142) was the first delivered, although a different account identifies GN 200-203 (built June 1947) as the first. So yes - inconsistent.  This was a significant upgrade, as the belt-driven auxiliaries were replaced by gear-driven ones.  However, locomotives combined to be built under the original specification simultaneously, into 1949.

The New Haven diagram only lists one auxiliary generator, the 5GY24A, which was the belt-driven generator used in specification E-1661.  This would imply that the first run (December 1947-January 1948) and second run (November-December 1948) were all built to specification E-1661, even though locomotives were already being built with Specification E-1661A. 

Although many references group E-1661A and E-1661B specification locomotives together, only the nine MLW-built units were specification E-1661B.

According to Kirkland, there were 35 locomotives built to specification E-1661, the last of which were five CGW units (53-57) built August 1949.

There were fifteen built before March 1947:

• D&M (5)
• D&H (7)
• CIL (1)
• Demonstrator (2)

And two were exported to Ontario Northland. Including the final five units for CGW, that leaves only thirteen of the thirty-five which isn't enough to cover all seventeen of the New Haven units. It is likely that CGW 50-52 were also this specification. That leaves only ten units built for the NH.

In that case, the first order of ten (0500-0509) would be specification E-1661 with belt-drive auxiliaries, completing the 35 units built under that specification. This makes sense.

But that would mean the second group of seven (0510-0516) had to have been built under the second E-1661A specification and not the earlier one, and the NH diagram is missing information.  The alternative is that published accounts (which seems to start with Kirkland) of only 35 locomotives being built under specification E-1661 is inaccurate.  I suspect it's probably a 50-50 chance of either.

In theory, all of these records are held by the ALCO Historical & Technical Society, but they aren't in a position to find them right now due to some reorganization going on now.

Specification E-1661C

Multiple sources also indicate that there were 31 units built under specification E-1661C.  The major upgrade here was to the 244C prime mover with 1,600 hp. Seaboard was the first to receive them, along with WM and Erie. The thirty-first unit was Demonstrator 1600.

But the first eight "RS-3" units built, for Great Northern (197-224) were also built to this specification. They had the new RS-3 carbody, but the 244C (instead of 244D) prime mover, and other mechanical aspects of the RS-2.  These changes were iterative, essentially the next step in the evolution of the major components. But for all practical purposes, these are RS-2 locomotives, not RS-3s.

This assessment is in line with Alco's practices, too, where the mechanical specifications is what determined the type of locomotive.  In 1962, when rebuilding RS-3 locomotives for the NH, they were initially going to be rebuilt as (per Alco documentation) DL-701 engines. That is, they would receive 251 prime movers and, as far as Alco was concerned,  they would be RS-11 locomotives, even though they would have retained their RS-3 bodies. The financial condition dictated otherwise, and they were instead simply rebuilt with 244H, aka model 250 prime movers and other upgrades. 

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Anyway, here's a spreadsheet that attempts to compile all of the specification numbers for Alco RS-2s. Hopefully somebody can confirm whether the second group of NH RS-2s were built under Specification E-1661 or E-1661A.

Alco RS-2 Build List and Specifications