Due to a motive power shortage during 1978 and early 1979, Caltrain(or was it still SP?) borrowed a number of Amtrak's GE built P30CH engines to power commuter trains between San Francisco and San Jose. The first photo is train 171 with Amtrak 720 on August 6, 1978 passing the San Jose Roundhouse while 700 and 705 sit on the ready track.
This photo shows 705 leading 502, 618, and 539 on the point of the Coast Starlight after commuter duties had ended and the P30CHs were being transferred to Los Angeles. The trestle is over Stenner Creek at San Louis Obispo, CA. The date is April 2, 1979.