EMD SD40-2S

Infobox Locomotive
name = EMD SD40-2S
powertype = Diesel-electric
builder = General Motors Electro-Motive Division
aarwheels = 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.cite web
url = http://utahrails.net/all-time/all-time-46.php#sd40-2s-3805
title = All-time UP Diesel Roster, Part 46
author = Strack, Don
work = Utah Rails
accessdate = 2006-11-18] Nine of these locomotives were constructed, five in April and May 1978 for Burlington Northern as EMD order #776083cite web
url = http://www.trainweb.org/emdloco/776083.htm
title = EMD 776083, SD40SS, BN 7049-7053
work = The Unofficial EMD Homepage
accessdate = 2006-11-18] (BN 7049–7053), and four for Union Pacific in November 1980 as EMD order #80653.cite web
url = http://www.trainweb.org/emdloco/806053.htm
title = EMD 806053, SD40SS, UP 3805-3808
work = The Unofficial EMD Homepage
accessdate = 2006-11-18] (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, 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.

After a year's testing, the UP locomotives were fitted with standard engines and turbochargers. It is probable that the BN locomotives were also similarly refitted.Fact|date=February 2007 All of the BN units are still in service with successor BNSF Railway, while of the UP locomotives two remain in service with UP, renumbered to UP 3412 [cite web
url = http://www.trainweb.org/utahrails/up/3kupr.html
title = November 2003 UP Roster Changes
work = Utah Rails
author = Strack, Don
accessdate = 2006-11-18] and 3277 [cite web
url = http://www.trainweb.org/utahrails/up/4fupr.html
title = June 2004 UP Roster Changes
work = Utah Rails
author = Strack, Don
accessdate = 2006-11-18] 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.

References