Alco "RS27" Locomotives: Specs, Roster, Data Sheet

Last revised: December 27, 2024

The RS27 was a late model of the Road Switcher (RS) series that produced more than 2,000 horsepower. However, the model was unsuccessful, a common theme of Alco production during this time.

The RS27 looked very much like Alco's later models and was the first to receive the builder's new styling. By the late 1950s Alco was slipping further behind the Electro-Motive Division

Overview

Alas, before the decade was over it would also be competing with one-time ally General Electric. Interestingly, examples of this rare Alco model can still be found, in service on short line Minnesota Commercial (a haven for Alcos).

The locomotives were purchased from the Green Bay & Western, which had purchased them from the Chicago & North Western (#901 and #903). Aside from RS27's, their roster over the years has included RS3's, C424's, and even Montreal builds (RS18's, RS23's, M630's, and M636's).

Photos

A pair of Alco's RS27 demonstrators, #640-2 and #640-1, circa 1959. The lead unit (#640-2) became Union Pacific #675 while the trailing unit (#640-1) was sold to the Pennsylvania and became #2415. The three other demonstrators (#640-3 - #640-5) were also acquired by UP becoming #676-678. George Hockaday photo.

The RS27 began production in 1959 using a B-B format (two axles per truck) and producing a hefty 2,400 horsepower for a somewhat small, four-axle unit.

As with other late-model RS designs the RS27 came in a standard low-nose setup using Alco's much more reliable 251B prime mover.

Design

In terms of the company's history as a locomotive builder, the RS27 offered the first glimpse of its Century series, which began production in 1963. The model retained the flush, long hood with the cab and the classic notched corners on the carbody remained.

However, the cab featured a slight design change with raised number boards and headlights, and the nose was shorter giving the locomotive a more blunted appearance.

From an exterior standpoint the RS27 began the common look of second-generation designs, as GE used a similar setup with its U25B, and EMD did the same beginning with its GP18, GP20,and GP30 models.

Perhaps it was due to Alco's earlier troublesome engine designs that kept railroads away but whatever the case the builder found little success with the RS27 selling less than thirty units with the Pennsylvania Railroad purchasing the most (15). The year 1959 was not a particularly good one for Alco.

It was increasingly losing market share to EMD, had not cataloged a successful locomotive since the RS3 finished production in 1956 (although its RS11 design did sell relatively well).

Pennsylvania RS27 #2404 is seen here near Chicago, circa 1965. Fred Byerly photo. American-Rails.com collection.

Additionally, that year GE ended its five decade partnership with the company when it released its own line of diesels beginning with the U25B (which ironically far outsold the RS27).

From an operational standpoint, the RS27 varied little from the RS11 aside from the additional horsepower. It actually offered less continuous tractive effort (42,000 pounds) but more starting effort (66,000 pounds).

As had been the case for nearly two decades when the RS27 was produced, internal components like traction motors, generators, and air brakes/compressors came in from GE and Westinghouse.

Data Sheet and Specifications

Alco Class	404-DL-257
Entered Production	12/1959 (Demo #640-1)
Years Produced	12/1959-10/19/1962
Model Specification	DL640
Engine	251B, V-16
Horsepower	2,400
RPM	1,025
Carbody Styling	Alco
Length (Between Coupler Pulling Faces)	57' 2"
Weight	256,800 Lbs.
Dynamic Brakes	Optional
Trucks	B-B
Truck Type	Swing Bolster, Drop-Side Equalizer (AAR Type-B)
Truck Wheelbase	9' 4"
Wheel Size	40"
Traction Motors	GE 752 (4)
Traction Generator	GT581
Steam Generator	Optional
Gear Ratio	65:18
Tractive Effort Rating	64,200 Lbs.
Top Speed	75 MPH

Production Roster

Total Built = 27

Owner	Road Number(s)	Construction Number(s)	Completion Date
Alco Demonstrator *	640-1, 640-2, 640-3, 640-4, 640-5 (Demo's #640-2 thru #640-5 to Union Pacific)	83555-83559	12/1959-1/1960
Chicago & North Western	900-903	83601-83604	3/1962
Green Bay & Western	310	83600	11/1960
Pennsylvania	2400-2407	83607-83614	10/1962
Pennsylvania	2408-2414	84373-84379	10/1962
Soo Line	415-416	83605-83606	4/1962
Union Pacific	675-678 (Ex-Demo's #640-2 thru #640-5)	4	12/1959-1/1960

* The first demonstrator, #640-1, was returned to Schenectady and rebuilt as a C424 and assigned new construction number 84558. It was subsequently sold to the Pennsylvania Railroad on October 1, 1963 as #2415.

Sources

Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.

Kirkland, John F. Diesel Builders, The: Volume Two, American Locomotive Company And Montreal Locomotive Works. Glendale: Interurban Press, 1989.

Pinkepank, Jerry A. Diesel Spotter's Guide. Milwaukee: Kalmbach Publishing Company, 1967.

Solomon, Brian. Alco Locomotives. Minneapolis: Voyageur Press, 2009.

An American Locomotive builder's photo at its Schenectady plant featuring one of the Soo Line's two RS27's (#415) it purchased in 1962.

Reception

In the end the model proved another abysmal failure for Alco as just four Class I railroads ultimately purchased the RS27; the aforementioned Pennsylvania, Soo Line, Chicago & North Western, and Green Bay & Western.

Of note, however, Union Pacific did purchase two of the demonstrators, #640-2 and #640-3. Somewhat unsatisfied, UP returned them to the Montreal Locomotive Works where they were later resold.

Today, the Minnesota Commercial is apparently quite happy with its two RS27s as the railroad has kept them on its roster for nearly three decades now.