This is a Baldwin S-12 switcher engine on display at the Railroad Museum of Pennsylvania in the town of Strasburg.

(James St. John, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons)

 

BLW Group logo

BALDWIN-LIMA-HAMILTON S-12 DIESEL-ELECTRIC LOCOMOTIVE

The BLH S12 was a 1,200-horsepower (890 kW) diesel-electric switcher locomotive manufactured by Baldwin-Lima-Hamilton. Utilizing a turbocharged 6-cylinder version of the powerful 606A diesel prime mover, S12s were known for their "lugging" power, despite being temperamental. Like most BLH switchers, the S12 had AAR Type-A switcher trucks in a B-B wheel arrangement. 451 units were built between 1951 and 1956, when BLH left the locomotive market.

 

Southern Pacific Baldwin S12 1506, date, location and photographer unknown.

(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/50569798847/in/photostream/)

 

Previous models

Baldwin made a number of switchers with similar dimensions and body styles. The first body style, used in VO models, had a slightly pointed nose with a round radiator opening. The second and third body style, almost indistinguishable and used interchangeably, had a flat nose and rectangular radiator opening. Various exhaust stacks were used, and are not an effective spotting feature, except that turbocharged models always had one large stack offset to the side.

The VO-660 was built between April 1939 and May 1946. It was powered by a naturally aspirated six cylinder engine rated at 600-horsepower (450 kW). 142 were built. Baldwin replaced the VO-660 with the model DS-4-4-660 in 1946.

The VO-1000 was built between January 1939 and December 1946. It was powered by a naturally aspirated eight cylinder engine rated at 1,000-horsepower (750 kW). Some had the Batz truck originally developed by the Atchison, Topeka and Santa Fe Railway as a leading truck for steam locomotives. 548 VO-1000s were built.

The DS-4-4-660 was built between 1946 and 1949. It replaced the 600-horsepower (450 kW) VO-660 as the low power companion to the DS-4-4-1000 models. 139 were built.

The DS-4-4-1000 was a 1,000-horsepower (750 kW) model built between 1946 and 1951. The first units (56 locomotives) were powered by an 8-cylinder normally aspirated prime mover, but from 1948 a change was made to a 6-cylinder turbocharged engine. A total of 502 were built.

 

Milwaukee Road Baldwin S12 923 at Minneapolis, Minnesota, June, 1975. Photographer unknown.

Built by Baldwin in December, 1950, as Milwaukee Road 1908. It was renumbered Milwaukee Road 923 in July, 1959.

It was retired in April, 1976, and scrapped at the Milwaukee shops in September.

(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/50576654478/)

Reference: J. Michael Gruber, Diesels of the Milwaukee Road, Volume 1, Withers Publishing, 2010, pg 46

 

Original Buyers 

Railroad Quantity Road number Notes
Baldwin-Lima-Hamiton (demonstrators) 2 1200–1201 to Rock Island 758–759
Atlanta and West Point Rail Road 1 678
Akron and Barberton Belt Railroad 2 27-28
American Smelting and Refining Company 2 1954–1955
Apache Railway 1 600
Armco Steel, Hamilton, Ohio 1 706
Baltimore and Ohio Railroad 5 463–467 Renumbered 9274–9278
Calumet and Hecla Mining Company 1 203
Central of Georgia Railway 4 311–314
Central Railroad of New Jersey 7 1053–1059
Chicago and North Western Railway 16 1073–1076, 1106–1109, 1117–1121, 1126–1128
Chicago, Milwaukee, St. Paul and Pacific Railroad (“Milwaukee Road”) 21 1905–1925 Renumbered 900–914, 920–925 (not in order)
Copper Range Railroad 1 200
Erie Railroad 12 617–628
Erie Mining Company 4 400–403
Great Northern Railway 5 24–28
Kansas City Southern Railway 4 1160–1163
Lehigh Valley Railroad 14 230–243
Michigan Limestone 2 116–117
Missouri-Kansas-Texas Railroad 15 1201–1210 Renumbered
Monongahela Railway 27 400–426
Missouri Pacific Railroad 20 9200–9219 Renumbered 1260–1279
Missouri Pacific (International-Great Northern Railroad) 10 9220–9226, 9230–9232
Missouri Pacific (St. Louis, Brownsville and Mexico Railway) 3 9227–9229
Missouri Pacific (Union Railway of Memphis) 7 9233–9239
McCloud River Railroad 2 30–31 No. 31 built as 800 hp; convertible to 1,200 hp (but never converted)
New Orleans Public Belt Railroad 2 61–62
New York Central Railroad 21 9308–9328
Oliver Iron Mining Company 1 933
Patapsco and Back Rivers Railroad 3 345–347
Pennsylvania Railroad 87 8100–8104, 8732–8796, 8976–8993 PRR Class BS-12m
Pennsylvania-Reading Seashore Lines 11 6017–6021, 6028–6033
Rayonier, Inc. 2 201–202
Seaboard Air Line Railroad 10 1462–1465, 1476–1481 to Seaboard Coast Line Railroad 203–206, 217–222
Sierra Railroad 2 40, 42
Southern Railway 10 2290–2299
Southern Pacific Company 56 1442–1513, 1539–1550
Southern Pacific (Texas and New Orleans Railroad) 3 105–107
Tennessee Coal, Iron and Railroad Company 8 1200–1207
Tennessee Valley Authority 4 1–3, 200
Terminal Railroad Association of St. Louis 4 1250–1253
United States Air Force 2 1841–1842
United States Army 1 65-11391
United States Navy 13 65-00292–65-00294, 65-365–65-00374
U.S. Steel, Geneva Steel Works 3 33–35
U.S. Steel, Homestead Steel Works 1 GE1
U.S. Steel, Morrisville, Pennsylvania Works 9 GE2–GE8, GE17–GE18
Wabash Railroad 5 305–309
Total 451

Southern Pacific Baldwin S12 1393 in a builder photo at Eddystone, Pennsylvania, August, 1948.

SP 1393 was the first unit of an order for ten S12's built in August and September, 1948.

It was renumbered SP 1863 in the 1965 general renumbering.

It was retired on May 18, 1972, and traded in to EMD in September, 1972.

(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/50437034373/)

 

 

Central of New Jersey 1058 (Baldwin S12) at the Elizabeth, NJ Shops on November 8, 1969.

(Roger Puta, railfan 44 - https://www.flickr.com/photos/129679309@N05/22528677335/, Public Domain)

 

Surviving units

At least six intact examples of the S12 are known to survive at railroad museums. SMS Lines operates S12 No. 301 at the Penn Warner industrial park at Morrisville, Pennsylvania. One unit that was converted from a Baldwin DS-4-4-1000 is in service on the Whitewater Valley Railroad.

 

Overview

Type and origin
Power type: Diesel-electric
Builder: Baldwin Locomotive Works
Model: S12
Build date: January 1951–October 1956
Total produced: 451
Specifications
Configuration: AAR B-B
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge
Trucks: AAR type A
Wheel diameter: 40 in (1,016 mm)
Minimum curve: 44° (133.47 ft or 40.68 m radius)
Wheelbase: 30 ft 8 in (9.35 m)
Length: 48’
Width: 10’
Height: 14’
Locomotive weight: 240,000 lb (108,862 kg)
Prime mover: 606A
RPM range: 625 rpm max
Engine type: Four-stroke diesel
Aspiration: Turbocharger -: Elliott Company H503 (215 hp)
Displacement: 1,979 cu in (32.43 L) per cylinder; 11,874 cu in (194.58 L) total
Generator: Westinghouse YG40D
Traction motors: Westinghouse 362D (x 4)
Cylinders: 6
Cylinder size: 12+3⁄4 in × 15+1⁄2 in (324 mm × 394 mm)
Performance figures
Maximum speed: 60 mph (97 km/h)
Power output: 1,200 hp (895 kW)
Tractive effort: Starting: 72,000 lbf (33,000 kgf) @30% / Continuous: 34,000 lbf (15,000 kgf) @10.8 mph (17.4 km/h)
Career
Disposition: 6 preserved, remainder scrapped