Commuting on the Southern Pacific
The Southern Pacific operated commuter trains between San Francisco to San Jose, California from the early 1900’s until the service was taken over by Caltrain in 1980.
Conventional passenger cars were the norm until 1955, when the SP received ten 145-seat double-deck gallery cars from Pullman Standard. 21 more arrived in 1956-1957.
By 1969, the commuter fleet consisted of 46 bi-levels and 55 standard coaches.
Motive power during the diesel era was 14 Fairbanks-Morse H-24-66 Trainmasters, in addition to 11 specially equipped GP9’s.
The conductor of SP commuter train 147 signals to depart Millbrae, CA on June 20, 1975
Note the interesting features that were unique to the GP9’s assigned to commuter service. Roof-mounted air tanks, steam generator stack, and the red “wings” on both ends of the unit.
Anybody care to venture a guess why there were wings on both ends of the passenger GP9’s?
Update: From comments, reader Ron Kiser replied with the correct answer: The wings on both ends indicated that the engine has dual controls. A control on both sides of the cab.
Southwest Rails 
The wings on both ends indicated that the engine has dual controls. A control on both sides of the cab. BTW, many of these geeps came through Oklahoma City on the Tucumcari to Memphis Rock Island passenger train on a regular basis.
Great picture of a nice, clean engine and train. I sure do miss those signal lights on the SP units.