EMD SD40-2S

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EMD SD40-2S

Power type	Diesel-electric
Builder	General Motors Electro-Motive Division
AAR wheel arr.	C-C

The EMD SD40-2S (also known as the SD40-2SS or SD40SS) was an experimental test bed variant of the popular EMD SD40-2 diesel locomotive, produced by General Motors Electro-Motive Division.^[1] Nine of these locomotives were constructed, five in April and May 1978 for Burlington Northern as EMD order #776083^[2] (BN 7049–7053), and four for Union Pacific in November 1980 as EMD order #80653.^[3] (UP 3805–3808).

These locomotives were fitted with larger engine blocks, larger turbochargers, and two-speed radiator fans which were expected to improve cooling and reliability. The four UP units, but not the five BN locomotives, were fitted with an extended long hood, about 28 inches longer^[1], to take enlarged radiators. Instead of the standard seven access doors under the radiators, these units had eight.

It has been commonly believed these units were fitted with higher-capacity AR16 alternators, traction motors, possibly increased engine power, and Super Series speed control; however, Don Strack's research in Union Pacific's archives has proven that the UP units at least were not so equipped.^[1]

After a year's testing, the UP locomotives were fitted with standard engines and turbochargers.^[1] It is probable that the BN locomotives were also similarly refitted.^{[citation needed]} All of the BN units are still in service with successor BNSF Railway,^[2] while of the UP locomotives two remain in service with UP, renumbered to UP 3412^[4] and 3277^[5] from UP 3806 and 3807. Former UP 3805 is now in service with the Iowa, Chicago and Eastern Railroad as ICE 6406, and former UP 3808 now belongs to the Evansville Western Railway as EVWR 6003.^[3]

[edit] References

1. ^ ^{a b c d} Strack, Don. All-time UP Diesel Roster, Part 46. Utah Rails. Retrieved on November 18, 2006.
2. ^ ^{a b} EMD 776083, SD40SS, BN 7049-7053. The Unofficial EMD Homepage. Retrieved on November 18, 2006.
3. ^ ^{a b} EMD 806053, SD40SS, UP 3805-3808. The Unofficial EMD Homepage. Retrieved on November 18, 2006.
4. ^ Strack, Don. November 2003 UP Roster Changes. Utah Rails. Retrieved on November 18, 2006.
5. ^ Strack, Don. June 2004 UP Roster Changes. Utah Rails. Retrieved on November 18, 2006.