EMD SD40-2 Nose Lengths

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This page was last updated on May 17, 2024.

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Overview

During an online discussion in 1999 and 2000 about SD40-2 nose lengths, I added that during 1977 and 1978 I was able to measure each of the various nose lengths on UP's units. This was while I was employed by Union Pacific as a boilermaker and carried a tape measure with me at all times. Don Dover, editor of the locomotive news magazine, Extra 2200 South and I were talking regularly about compiling an all-time roster of Union Pacific diesel locomotives, and Don mentioned the need for definite measurements of nose length variations on newly delivered Union Pacific SD40-2s. I was able to provide the needed information within a couple days.

EMD SD40-2 Production

Across the years of production of EMD's SD40-s, from 1972 to 1984 in the United States, the locomotives were equipped with five different nose lengths.

(Union Pacific received new SD40-2s delivered from EMD between 1972 and 1980.)

Regardless of the nose length, the drop from the cab wall, to the front of the nose, was two inches difference in height.

The first SD40-2s built by EMD from 1972 had the original 81-inch low nose.

EMD built two versions of the 116" nose. From June 1974 through December 1977, the 116" extended nose was constructed by adding a 35" extension onto the rear of the existing 81" nose, for a total length of 116". The extension had a flat top, while the 81" nose had a sloped top. The resulting nose had two slopes, and has become known as a "dual slope 116" nose."

The second 116" nose, which went into production concurrent with the 88" standard nose, in January 1977, has a constant slope from the cab windshield to the tip of the nose. This nose has become known as a constant slope 116" nose.

EMD switched from 116 inches to 123 inches at the same time as the switch from 81 inches to 88 inches. The extra seven inches was needed to gain extra room for water coolers, that had to be removed from the cab interior in order to comply with the new AAR clean cab regulations.

UP SD40-2 Noses

In June 1974 Union Pacific began receiving new SD40-2s with an extended low nose, which railfans immediately began calling "snoots." This early version of the extended low nose consisted of the standard 81-inch nose and a 35-inch flat extension, making a total length of 116 inches.

The first units with extended low noses were the 45 units in the 3243-3287, which included the 32 units that were delivered as UP 8003-8034, and later renumbered back to their 3243-3274 number slots. These units were built in June and July 1974 and have the grid style radiator screens, and ratchet style hand brakes.

The Union Pacific was the only railroad to receive the dual slope 116" nose. Two handbrake options were available on this nose, the ratcheted lever and brake wheel. UP units 3243 through 3287 were equipped with the ratcheted lever, and units 3288 through 3304 received the brake wheel.

In January 1977, EMD changed the dual-slope design to a constant-slope design, retaining the overall 116-inch length.

In February 1977, the UP began receiving constant slope 116" nose SD40-2s, and all were equipped with brake wheels. The SP received 14 SD40-2s with the constant slope noses, but all of them were equipped with the ratcheted lever handbrake.

All later UP snoots are the 116" constant-slope design, numbers as UP 3335-3488 (154 units, built from February 1977 to June 1978)

In December 1978, starting with UP 3410, Union Pacific began receiving locomotives with EMD's new standard 88-inch low nose.

What's Inside

One of the reasons UP adopted the longer nose design so early in 1974 was the large Motorola radios the road used. With its mounting base, these radios were six inches high, 14 inches wide, and 18 inches deep. The longer nose allowed more room. This would have been to be in compliance with Clean Cab requirements, more space in the nose allowed UP to move their radios from atop the control stand.

LocoTrol -- "The UP originally bought the 116" nose to house Locotrol radio equipment. At the time, they were experimenting with Locotrol on the SD45s, which had the 81" nose. This caused them to move the cab signal equipment to a box located on the walkway behind the cab on the fireman's side. The additional space in the 116" nose would give them room for both the LocoTrol equipment, and the coded cab signal equipment. The Locotrol did not prove successful for the UP, and no systems were ever installed on the SD40-2s. They continued to order the long noses, but eventually switched back to the standard nose." (Steve Orth, email dated November 1, 1999)

Longer noses on UP's SD40-2s were needed to move the Coded Cab Signal magnetic valve from under the cab floor. Newly adopted FRA rules required that the valve be changed every 18 months, and access to the under-floor location was difficult. In the longer noses, the valve was located behind the door adjacent to the hand brake.

The longer nose allowed the water cooler to be moved out of the cab interior, to comply with the new AAR "Clean Cab" rules adopted in late 1976.

Also, the longer noses included a separate room for the onboard chemical toilet, and an enclosed space for better ventilation.

Summary

Here is a summary of UP's SD40-2s, not counting the MP, C&NW, and MKT units (sixteen orders spanning eight years of production, from 1972 to 1980).

Noses

More Information

Wikipedia article for the EMD SD40-2, and its variants

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