Introduced in the mid 40s just as many streamlined trains began to hit the high iron, the PA was the American Locomotive Company's answer to EMD's E-units. Packing 2,000 horses under the hood, these graceful machines featured rounded lines sweeping back from the nose and decorative trim behind the cab windows. They became favorites with modelers and railfans, many of whom felt PA stood for Perfect Alco. Walthers PROTO N PA-1 and PB-1 boosters feature a heavy cast-metal frame, five-pole motor and dual flywheels for smooth, reliable performance. Other features include detailed plastic bodies with accurate paint schemes and AccuMate(R); knuckle couplers. Available in sets or as single PA-1 units.