ALCO S-5 Diesel-Electric Switcher Locomotive
The Alco S-5 (DL 421A) was a diesel-electric locomotive of the switcher type rated at 800 horsepower (600 kW), that rode on two-axle trucks, having a B-B wheel arrangement.
This was Alco's second attempt to build a replacement 251-engined switcher to replace the 539-engined S-3 and S-4. Only seven were sold. The demonstrator unit was ALCO specification DL421 and the six production units were ALCO specification DL421A. Alco fitted the 251A engine in its replacement, the S-6 with power output raised by 100 horsepower (75 kW).
Railroad: Alco (demonstrator)
Road numbers: 909
Railroad: Boston and Maine Railroad
Road numbers: 860–865
ALCO S-5 Overview
Type and origin
Power type: Diesel-electric
Serial numbers: 80915–80921
Model: S-5 (Specification DL421 and DL421A)
Build date: June 1954
Total produced: 7
AAR wheel arrangement: B-B
Gauge: 4 ft 8 1⁄2 in (1,435 mm)
Prime mover: ALCO 251
Cylinders: Straight 6
Power output: 800 hp (600 kW)
Boston & Maine ALCO S-5 No. 864 in Boston in September of 1965. Photo by Roger Puta.
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Text: wikipedia.org. Images: Public Domain; http://www.commons.wikimedia.org (unless otherwise specified) and 17 U.S. Code § 107 fair use. References: Lewis, Robert G. The Handbook of American Railroads. New York: Simmons-Boardman Publishing Corporation, 1951, 2nd Edition 1956. Site Map Contact webmaster HERE.