ALCO S-6

The Alco S-6 (specification DL 430) was a diesel–electric switcher locomotive constructed by ALCO of Schenectady, New York; a total of 126 locomotives were built between May 1955 and December 1960. The S-6 was an improved version of the earlier S-5.

ALCO S-6
SP No. 1231 at El Centro, California, in 1970
Type and origin Power type Diesel Builder ALCO Model S-6 Build date May 1955–December 1960 Total produced 126
Specifications Configuration: ​  • AAR B-B  • UIC Bo′Bo′ Gauge 4 ft 8+1⁄2 in (1,435 mm) Length 45 ft 5 in (13.84 m) Width 10 ft (3.05 m) Height 14 ft 8 in (4.47 m) Loco weight 230,000 lb (104.3 tonnes) Fuel capacity 635 US gal (2,400 L; 529 imp gal) Lubricant cap. 140 US gal (530 L; 120 imp gal) Coolant cap. 110 US gal (420 L; 92 imp gal) Sandbox cap. 26 cu ft (0.74 m3) Prime mover ALCO 6-251A or B RPM range 375–1000 rpm Engine type Four-stroke diesel Generator GE GT-533 (or GE GT-584) Traction motors 4 × GE 731 (GE 752 optional[1]) Cylinders Straight 6 Cylinder size 9 in × 10+1⁄2 in (229 mm × 267 mm)
Performance figures Maximum speed 60 mph (97 km/h) Power output 900 hp (670 kW)
Career Locale United States, Mexico
[2]

Design

Visually indistinguishable from the S-5, the S-6 used an ALCO 251A or 251B prime mover rated at 900 horsepower (670 kW). The locomotive rode on two-axle AAR trucks, giving a B-B wheel arrangement. ALCO produced a cow–calf variant for the Oliver Iron Mining Company designated SB-8/SSB-9, two sets were produced of this version.^[3]

Original owners

Railroad	Quantity	Road Number	Notes
Allied Chemical Company	1	110
ARMCO Steel	1	1202
B. Perini & Sons Construction Company	1	101	to Upper Merion and Plymouth Railroad 101
Belt Railway of Chicago	1	420
Ferrocarril Chihuahua al Pacífico	1	60	Renumbered 106
Cia Fundidora de Hierro y Acero	3	1–3
Ferrocarril del Pacífico	24	701–723
Ferrocarriles Nacionales de México	1	5300
Northern Pacific Railway	1	750	to Burlington Northern Railroad 950
Ohio River Company (ORCo)	1	56
Republic Steel	3	153, 317, 318
Secretaria de Comunicaciones de Obras Publicas (SCOP)	3	7133-1, 2, 3	to Ferrocarril del Sureste (same numbers)
Sheffield Steel	2	15, 16
Southern Pacific Railroad	70	1033–1082, 4634–4645	renumbered 1200–1257, 1270–1281
South Buffalo Railway	6	40–45
Tennessee Copper	1	107
Upper Merion and Plymouth Railroad	1	61
U.S. Pipe and Foundry	1	38
Columbia Geneva Steel	1	1
Western Maryland Railway	2	151, 152
Ferrocarriles Unidos de Yucatán	1	301

In popular culture

• In Back to the Future Part III, two double headed S-6 locomotives destroyed the DeLorean time machine, when it returned to 1985.

See also

• List of ALCO diesel locomotives
• List of MLW diesel locomotives