Alcomotive
Grandson of an ALCO Builder
The original UP 1870 was a EMD TR5A....UP 1870-1877 were assigned to helper service on the South-Central District during early 1953; during February and March 1953 each unit had the D.S. (Diesel Switch) prefix removed from its 1870-series number. UP 1870-1872 were modified with 1400 gallon fuel tanks (originally equipped with 600 gallon fuel tanks) and air reservoirs on top of car body in September 1968 for service on the North Platte, Neb., hump yards. After being modified, they had 521,600 pounds total cow/calf operating weight. Then 7 units were built into SW10s units 1871 thru 1877. 1870 was the only one not re-built into a SW10. It was built in 1951 and retired in June 1976.
As for Athearn these were a real goof in being speced out as what it was intended for. Because it was to be a SW7 but for this unit number it should a been a EMD TR5A ...NOT... the latter nor could it have been a SW1500. So all in all the mold is in fact SW7/9 shell.
Between the time of UPs first Diesel switcher locomotives in 1939 and the 1982 merger with Western Pacific and Missouri Pacific, Union Pacific owned 118 non-EMD yard switchers. Included were 54 Alco S-2s, 45 Alco S-4s, six Baldwin VO 1000s, five Baldwin DS-4-4-10s, five Fairbanks-Morse H10-44s, one single Alco S-3 and a single Alco HH-1000, both of which came to UP with the purchase of the Mount Hood Railway in 1968, and finally, a single General Electric 44-ton center-cab switcher.
continued...http://www.utahrails.net/articles/up-sw-other.php the history of the D.S. designation....first switcher was in black by the way....
As for Athearn these were a real goof in being speced out as what it was intended for. Because it was to be a SW7 but for this unit number it should a been a EMD TR5A ...NOT... the latter nor could it have been a SW1500. So all in all the mold is in fact SW7/9 shell.
Between the time of UPs first Diesel switcher locomotives in 1939 and the 1982 merger with Western Pacific and Missouri Pacific, Union Pacific owned 118 non-EMD yard switchers. Included were 54 Alco S-2s, 45 Alco S-4s, six Baldwin VO 1000s, five Baldwin DS-4-4-10s, five Fairbanks-Morse H10-44s, one single Alco S-3 and a single Alco HH-1000, both of which came to UP with the purchase of the Mount Hood Railway in 1968, and finally, a single General Electric 44-ton center-cab switcher.
continued...http://www.utahrails.net/articles/up-sw-other.php the history of the D.S. designation....first switcher was in black by the way....
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