SD50 No. 5512 Top view

As of December 1991


Rio Grande's seventeen SD50 units were an opportunistic purchase by the railroad, which was actually shopping for twenty more tunnel motors.  The SD50s became available when their order was cancelled by the Chessie, and since they were (theoretically) rated higher than the SD40T-2s, it was assumed that the same work could be done with three fewer SD50s.  It didn't really work out that way, as it turned out.  And when the tunnel motors were upgraded with PTC systems, the two types became functionally equivalent.

Rio Grande's SD50s came in a single group, although the last three units didn't show up on the property until two months after the rest.

Number Range Date Purchased Comments
5501 - 5517 Aug 1984  Several features differed from standard Rio Grande practice.

Specific information for individual units may be found on the Rio Grande Modeling & Historical Society's SD50 page.


(1) Pyle Gyralite on low nose. 

(2) Nose access hatch, common to 50- and 60- series models.

(3) 5-chime horn. 

(4) Antennae: Sinclair, mounted to right of centerline, and small whip antenna further back.

(5) 60-inch single dynamic brake fan. 

(6) Bell, mounted on right side of long hood.  the bell location and the 5-chime horn are Chessie features that really set these units apart from other Rio Grande diesels.

(7) Battery compartment doors with "mail-slot" vent.

 

Comments:
  • The Pyle lights were added by a third-party contractor just prior to delivery.
  • The dynamic brake fans are located further forward on SD50s than on earlier models.
  • Some of these horns were replaced with a standard Leslie P-3 even before the SP modifications began.  For instance, No. 5507 was sporting the Leslie before this photograph was taken.
  • The bell location, battery doors, and 5-chime horn are Chessie features that really set these units apart from other Rio Grande diesels.

The SD50s, being Rio Grande's newest six-axle units, were early candidates for modification to the new Southern Pacific Lines standards.  A number of them were repainted into the new "merger" paint scheme with SP speed lettering, lost their Pyle lights, had the horns moved to the long hood and replaced with a 3-chime version, and had ditch lights added.  After 1992, many of them worked in southern California on Tehachapi or Cajon passes, only returning "home" after the UP merger.  Now they're nearly all in UP yellow.

 


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2004, James R. Griffin.  All rights reserved.