During the first part of the diesel revolution the various builders favored full carbody "streamlined" designs, as opposed to the more utilitarian if easier-to-maintain "hood" units of today. One of Alco's entrants to this market was the FA, the smaller freight-hauling sister to the classic PA 6-axle passenger units.
Although the four-axle FA's ran as freight units in the U.S., the Canadian arm of Alco, Montreal Locomotive Works, built a total of 48 FP-4 units for the Canadian National for passenger service (34 FPA-4's and 12 FPB-4's). These units were the only FA's to be equipped with the second generation Alco 251 prime mover and each unit packed 1800 HP.
Here a classic matched A-B pair idle away their layover at the Grand Canyon, awaiting departure time for their return trip to Williams, AZ. The boxcar directly behind the locomotives is a head-end power car for the electrically-heated passenger cars.
Grand CanyonTo Be Worked