SD40T- 2.
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Builder :
General Motors Electro-Motive Division
Electricity :
Length :
70' 8 "
Width :
10' 4"
Height :
15' 8"
Weight :
388 - 410,000 lbs
Cylinders :
Wheel Diam :
Fuel Tank :
4400 gal (SP) 4000 gal (D&RGW)
Max Speed :
70 mph
Horsepower :
3000 hp

Unique to the Southern Pacific and Rio Grande railroads, Electror-Motive's DASH 2 "Tunnel Motor" was all about solving the problem of overheating in the prime mover whilst operating through the many tunnels that SP had on its mountainous routes acroos the Sierra Nevadas and Tehachapis. The problem was first encountered on their SD45 fleet. SP and EMD teamed up to come up with a drastically revised cooling system designed to draw in much cooler air in from down near the running boards.

Inspite of their different outward appearance that characterises the model, the "tunnel motors" differed from standard SD40-2s only in the radiator configuration. All units were built on a longer frame which not only accommodated the radiator revision but also enabled the units to be fitted with a longer range fuel tank. The "Rio Grande" units retained the standard fuel tank.

A total of 312 "tunnel motor" versions of the ubiquitous EMD SD40-2 were built and between 1974 and 1980 The delivery breakdown was as follows:- 229 units for the SP with a further 10 for the SSW and 73 for the D&RGW.