F-UNITS HAULING REVENUE FREIGHT IN 2013!: F-units were common power for freight trains on the Boston and Maine Railroad......in the 1950s! Today, a sight which hasn't been seen since the 1970s--and likely may not be seen again--occurred when F-units once again hauled revenue freight on the former B&M West End. After bringing the High Iron passenger excursion from Boston, MA to Mechanicville, NY on Saturday, Pan Am's two FP9As returned east on Sunday with a very short intermodal train for Ayer. Here the train is seen rounding "Pownal Curve" along the Hoosic River in Pownal, Vermont.