Baldwin "RS-12" Locomotives: Specs, Roster, Data Sheet

Last revised: December 28, 2024

The RS-12 was Baldwin's lightest road-switcher design in terms of horsepower, featuring just 1,200 HP.

As John Kirkland notes in his book, "The Diesel Builders: Volume Three (Baldwin Locomotives Works)," Eddystone never made a concerted effort to challenge Alco's success in this market with its popular RS-1.

Baldwin had a built a few 1,000 horsepower road-switchers (DRS-4-4-1000) for a few North American lines (Tennessee Central, Canadian Pacific, and Pennsylvania) but by and large stayed out of the market.

When the company upgraded its road-switchers with the 608A prime mover, it increased the DRS-4-4-1000 by 200 horsepower and renamed it the RS-12.

Baldwin put more effort into marketing this new variant but by the 1950s railroads were looking for greater power in an over-the-road locomotive. As such, the RS-12 saw few sales.

Today, there are several RS-12's preserved, most of Seaboard Air Line heritage; in addition, McCloud River Railroad #33 (only one of two built with dynamic brakes) can be found at California's popular Skunk Train while short line freight carrier Escanaba & Lake Superior owns eight units (all of Seaboard heritage).

Photos

Pennsylvania RS12 #8105. Author's collection. This unit was part of a batch of six (#8105-8110) to initially feature the high, short hood. This group did not feature dynamic brakes. In his book, "The Diesel Builders: Volume Three (Baldwin Locomotives Works)," John Kirkland notes the following: "As a consequence of carbody design changes that were made beginning in 1953 on the 1,600 hp road switcher models...certain changes were also made to the model RS-12 production beginning in 1954 in order to permit using the same jigs and fixtures for all road switcher production insofar as was possible. To accomplish this objective, the underframes were lengthened from 58 feet to 58'6" over couplers, and the level of the short hood was raised nearly to the level of the cab roof. The long hood, however, was not raised..."

Overview

The RS12 was Baldwin's lone light road-switcher the builder attempted to market although it appears to have been largely a half-hearted effort.

Incidentally, Baldwin's success in the diesel market began with a line of switchers and it had been producing small electric locomotives, such a various box cab designs, for years in conjunction with Westinghouse.

The RS12 was one of four road switcher models Baldwin-Lima-Hamilton offered in its new Standard line released in 1950.

These new locomotives sold far better than the company's earlier designs of the 1940s and one cannot help but wonder how successful BLH would have become had parent Westinghouse allowed it to continue refining its diesels.

Milwaukee Road RS12 #926 (built as #970) is seen here at Pigs Eye Yard in St. Paul, Minnesota during June of 1968. Fred Byerly photo. American-Rails.com collection.

In any event, BLH's new classification system was fairly straightforward and certainly much easier to decipher than its earlier system, partially based from the steam era.

In the case of the RS12 the "RS" referred to Road Switcher while the "12" regarded its 1,200 horsepower (the model was actually even easier to understand than the AS16, AS416, and AS616 classifications).

New York Central RS-12 #6225 (built as #5825) leads a two-coach commuter run northbound on the Putnam Division as the train crosses Croton Lake (New York), circa 1957. Meyer Pearlman photo. American-Rails.com collection.

The RS12 began production in April of 1951 and utilized Baldwin's 608A prime mover, an upgraded version of a previous engine. The locomotive featured a B-B truck setup (meaning there were two axles per truck) but no dynamic braking.

As with all of Baldwin's road switchers the RS12 used its standard carbody design; a short lead hood, offset cab, and trailing long hood. The look was actually quite pleasing with soft beveling and a flush roof line.

Overall, the RS12 was 58 feet in length and weighed in at a very light 133 tons (for a locomotive of its size). While rather long and light for its horsepower rating the locomotive included a starting tractive effort of 60,000 pounds and 32,000 pounds continuous.

Pennsylvania DRS-4-4-1000 #9277 is seen here at Camden, New Jersey, circa 1965. American-Rails.com collection.

DRS-4-4-1000 Roster

Owner	Road Number	Baldwin Serial Number	Construction Number	Completion Date
Tennessee Central	75	1	73706	7/13/1948
Tennessee Central	76	2	73707	7/13/1948
Tennessee Central	77	3	73708	8/3/1948
Canadian Pacific	8000	4	73967	1/21/1949
Canadian Pacific	8001	5	73968	1/19/1949
Canadian Pacific	8002	6	73969	1/11/1949
Canadian Pacific	8003	7	73970	1/26/1949
Canadian Pacific	8004	8	73971	1/27/1949
Canadian Pacific	8005	9	73972	1/25/1949
Canadian Pacific	8006	10	73973	1/25/1949
Canadian Pacific	8007	11	73974	2/28/1949
Canadian Pacific	8008	12	73975	2/21/1949
Canadian Pacific	8009	13	73976	2/3/1949
Canadian Pacific	8010	14	73977	2/9/1949
Canadian Pacific	8011	15	73978	2/10/1949
Canadian Pacific	8012	16	73979	2/11/1949
Pennsylvania	9276	17	74403	2/24/1949
Pennsylvania	9277	18	74404	2/24/1949
Pennsylvania	5591	19	74744	3/8/1950
Pennsylvania	5592	20	74745	3/10/1950
Pennsylvania	5593	21	74746	3/15/1950
Pennsylvania	5593	22	74747	3/17/1950

Data Sheet and Specifications

Entered Production	4/3/1951 (Pennsylvania #8975)
Years Produced	4/3/1951 - 5/15/1956
Baldwin Class	DRS-4-4-1200/1 SC
Engine	608A
Engine Builder	De La Vergne
Horsepower	1200
Carbody Styling	Baldwin
Length (Between Coupler Pulling Faces)	58'
Weight	325,000 Lbs
Height (Top Of Rail To Top Of Cab)	14'
Width	10' 2"
Trucks	B-B
Truck Type	GSC Swing Bolster, Drop Side Equalizers
Truck Wheelbase	9' 10"
Wheel Size	42"
Traction Motors	362DF (4)*, Westinghouse
Traction Generator	480FZ, Westinghouse
Auxiliary Generator	YG42B, Westinghouse
Gear Ratio	14:68
Tractive Effort Rating	32,400 Lbs at 11.4 mph
Top Speed	60 MPH

* Late variants were equipped with 362DZ model traction motors.

During the course of production there were several changes made to the RS-12, as is described in the following:

New York Central #5820-5836: Equipped with steam generators for passenger service and MU capability.

Pennsylvania #8105-8110: Frame length increased from 58' to 58' 6" (over couplers) and the short hood raised to nearly the height of the cab roof.

Kaiser Bauxite #101-104 and McCloud River Railroad #32-33: Equipped with 370DEZ traction motors with 15:63 gearing which increased continuous tractive effort to 48,000 Lbs at 7.6 mph.

Milwaukee Road RS12 #927 switches at the railroad's Minneapolis station in December, 1965. This was one of just two RS12s the company owned, and was originally numbered 971. Rick Burn photo.

Production Roster

Total Built = 50

Owner	Road Number	Baldwin Serial Number	Construction Number	Completion Date
Pennsylvania	8975	1	75116	4/3/1951
Chicago, Milwaukee, St. Paul & Pacific (Milwaukee Road)	970	2	75242	5/14/1951
New York Central	5820	3	75256	11/7/1951
New York Central	5821	4	75257	11/7/1951
New York Central	5822	5	75258	11/9/1951
New York Central	5823	6	75259	11/9/1951
New York Central	5824	7	75260	11/12/1951
New York Central	5825	8	75261	11/12/1951
New York Central	5826	9	75262	11/13/1951
New York Central	5827	10	75263	11/13/1951
New York Central	5828	11	75264	11/20/1951
New York Central	5829	12	75265	11/20/1951
New York Central	5830	13	75266	12/19/1951
New York Central	5831	14	75267	12/19/1951
New York Central	5832	15	75268	12/21/1951
New York Central	5833	16	75269	12/21/1951
New York Central	5834	17	75270	12/27/1951
New York Central	5835	18	75271	12/31/1951
New York Central	5836	19	75272	12/31/1951
Seaboard Air Line	1466	20	75475	5/13/1952
Seaboard Air Line	1467	21	75476	5/19/1952
Seaboard Air Line	1468	22	75477	5/21/1952
Seaboard Air Line	1469	23	75478	5/22/1952
Seaboard Air Line	1470	24	75479	5/22/1952
Seaboard Air Line	1471	25	75480	5/24/1952
Kaiser Bauxite Company	101	26	75486	4/30/1952
Kaiser Bauxite Company	102	27	75487	4/30/1952
Pennsylvania	8776	28	75663	9/17/1952
Chicago, Milwaukee, St. Paul & Pacific (Milwaukee Road)	871	29	75702	10/30/1952
Central Railroad Of New Jersey	1206	30	75446	1/30/1953
Central Railroad Of New Jersey	1207	31	75447	1/30/1953
Central Railroad Of New Jersey	1208	32	75448	1/30/1953
Central Railroad Of New Jersey	1209	33	75698	1/30/1953
Seaboard Air Line	1472	34	75765	1/8/1953
Seaboard Air Line	1473	35	75766	1/8/1953
Seaboard Air Line	1474	36	75767	1/12/1953
Seaboard Air Line	1475	37	75768	1/16/1953
Pennsylvania	8110	38	75955	2/15/1954
Pennsylvania	8105	39	75950	2/4/1954
Pennsylvania	8106	40	75951	2/4/1954
Pennsylvania	8107	41	75952	2/5/1954
Pennsylvania	8108	42	75953	2/5/1954
Pennsylvania	8109	43	75954	2/8/1954
Durham & Southern	1200	44	76001	3/26/1954
Durham & Southern	1201	45	76002	3/31/1954
Durham & Southern	1202	46	76003	3/30/1954
McCloud River Railroad	32	47	76024	4/29/1955
McCloud River Railroad	33	48	76105	4/29/1955
Kaiser Bauxite Company	103	49	76133	5/15/1956
Kaiser Bauxite Company	104	50	76134	5/15/1956

Sources

Kirkland, John F. Diesel Builders, The: Volume Three, Baldwin Locomotive Works. Pasadena: Interurban Press, 1994.

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

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

California Western RS12 #56 (built as McCloud River Railroad #33) lays over at the engine shop in Willits, California in May, 1973. Author's collection.

The New York Central would come to own the most, seventeen, which interestingly were supposed to be model LRS-1200s from Lima. However, due to the Lima-Baldwin merger NYC accepted the RS12 model instead.

In total, eight railroads purchased the locomotive; the aforementioned NYC and McCloud River as well as the Milwaukee Road, Jersey Central, Durham & Southern, Kaiser Bauxite, Seaboard Air Line, and ever-loyal Pennsylvania.

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