Among the engine sets handling switching duties at the Southern Pacific's large West Colton Yard in Bloomington, California, on March 2, 1975, are SP C-630 3147 and Braking Sled MW9100. The big Alco was originally SP 7805, built by Alco in March 1966 - and downgraded from mainline service to heavy switching/transfer service on 4/5/73. The Braking Sled began life as SP H24-66 4807 (built 12/53), renumbered to 3027 in 1965. These Fairbanks-Morse "Train Masters" spent most of their service lives in commute service, shutting commuters between San Jose and San Francisco. The last "Train Master" was taken out of service in January 1974, replaced by SDP45s that were no longer needed for Amtrak service (thanks to the delivery of Amtrak's new SDP40Fs). After tests in West Colton with H24-66 3028 used as a dead hump braking slded, a program was created to convert four of these big F-Ms to full-time Brake Sleds. These engines were to have their carbodies cut down, and they would have multiple-unit connections and independent air brakes. The cut-down hoods would be filled with concrete and these would be used only for their additional six axles of braking power, with a weight of 368,000 pounds. Four units 3025, 3027, 3032 and 3034 were held aside for conversion. The only one actuallly built, however, was MW9100, created from SP 3027.
