ALCO RSD-7
Encyclopedia
The ALCO RSD-7 was a diesel-electric locomotive of the road switcher
type built by ALCO at Schenectady, New York
between January 1954 and April 1956. Two versions were built, with the same RSD-7 model designation but different specifications and power ratings, although both used the ALCO 244 engine in V16
configuration. Specification DL-600, of which only two were built, developed 2250 hp (1700 kW); revised specification DL-600A, numbering 27 locomotives, was rated at 2400 hp
(1800 kW). The RSD-7 was superseded by the ALCO 251
-engined ALCO RSD-15
, which looks very similar.
Both rode on a pair of three-axle trucks
with all three axles on each truck powered; this is a C-C wheel arrangement. These trucks have an unequal axle spacing due to traction motor positioning; the outer two axles on each truck are closer together than the inner two. The six-motor design allowed better tractive effort at lower speeds.
Road switcher
A road switcher is a type of railroad locomotive used for delivering or picking up cars outside of a railroad yard. Since the road switcher must work some distance away from a yard, it needs to be able to operate at road speeds, it must also have high-visibility while it is switching, and it must...
type built by ALCO at Schenectady, New York
Schenectady, New York
Schenectady is a city in Schenectady County, New York, United States, of which it is the county seat. As of the 2010 census, the city had a population of 66,135...
between January 1954 and April 1956. Two versions were built, with the same RSD-7 model designation but different specifications and power ratings, although both used the ALCO 244 engine in V16
V16 engine
A V16 engine is a V engine with 16 cylinders. Engines of this number of cylinders are uncommon in automotive use.A V16 engine is perfectly balanced regardless of the V angle without requiring counter-rotating balancing shafts which are necessary to balance Straight-4 and odd number of cylinder...
configuration. Specification DL-600, of which only two were built, developed 2250 hp (1700 kW); revised specification DL-600A, numbering 27 locomotives, was rated at 2400 hp
Horsepower
Horsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...
(1800 kW). The RSD-7 was superseded by the ALCO 251
ALCO 251
The Alco 251 diesel engine was developed by the American Locomotive Company to replace the 244 and 539. The 251 was developed to be used in diesel locomotives, as a marine power plant in ships and as a stationary power generator.-Development:...
-engined ALCO RSD-15
ALCO RSD-15
The ALCO RSD-15 was a diesel-electric locomotive of the road switcher type built by ALCO of Schenectady, New York between August 1956 and June 1960, during which time 75 locomotives were produced...
, which looks very similar.
Both rode on a pair of three-axle trucks
Bogie
A bogie is a wheeled wagon or trolley. In mechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a railway carriage/car or locomotive, or sprung as in the suspension of a caterpillar...
with all three axles on each truck powered; this is a C-C wheel arrangement. These trucks have an unequal axle spacing due to traction motor positioning; the outer two axles on each truck are closer together than the inner two. The six-motor design allowed better tractive effort at lower speeds.