One Response to SW9 313

  1. Mark Davidson says:
    February 15, 2025 at 12:51 AM

    The locomotive is General Motors (GM) Electro-Motive Division (EMD) SW9 313.

    The original caption identified it as an EMD SW1500 locomotive SLSF 331. Note the earlier EMD first generation shorter or tighter radius curve cab roof. Second generation switchers had cab roofs with a much broader, longer or flatter radius curve. In the image the main air reservoir is shorter, with a large diameter (7’ x 21”) mounted lower adjacent to the fuel tank. Second generation switchers had longer, small diameter (12’ x 12”) air reservoirs mounted directly below the side sills.

    Another distinguishing feature is the long hood handrails. In the photograph note the yellow long hood side mounted horizontal handrail. On our later EMD switch engines the long hood side handrails were mounted on stanchions attached to the side sills. Also note the seven vertically stacked louvers in the hood side doors, a characteristic common to many first generation EMD switch engine locomotives.

    The Frisco adopted the Mandarin orange and white paint scheme on 2/14/1965. The first SW1500 locomotive, SLSF 315, was shipped on 10/11/1968. SW1500 331 was shipped 12/16/1969. All of these model units were delivered in the Mandarin orange and white paint scheme. As a result, no Frisco owned SW1500 was painted black and yellow.

    SLSF 313 was one of the original four SW9 units (SLSF 310-313) equipped with slow speed controls for use in pairs at the hump at Tennessee Yard in Memphis, Tennessee. A fifth unit, SLSF 309, later had the equipment added so it could serve as a backup unit when one of the original four units was out of service for maintenance or repair.

    Hope this helps.

    Thanks!

    Mark

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