They featured diamond-shaped twin-arm Stemmann pantographs, rounder windows, a right-side operating controls, center doors, and a different body shape.The Arrow I used Westinghouse SCR "Tracpak" propulsion units with 700 HP per car with four motors; while the Silverliners had GE air-cooled Ignitrons .Indeed, the Arrow II and the Silverliner IV share the same body shell, cab corner air scoops and single-arm Faiveley pantographs, with the primary differences being the shorter air intake hump on the roof, corresponding lack of dynamic brakes, and the inclusion of the high-level center door as on the Arrow I.From June 1978 until the summer of 1979, the Arrow IIs were leased to the Maryland Department of Transportation, where they bumped the last operating MP54s from service.Work began at Morrison Knudsen in January 1983, with the cars receiving several upgrades for compatibility with the Arrow IIIs.The sliding doors were rebuilt to be compatible with Arrow III circuitry, and to be sensitive to objects they encounter when closing.In 1997, the decision was made to retire them due to rotting floors and holes in the roofs, with ALP44s and Comet IV coaches (ordered for Midtown Direct service) in push-pull configuration as replacements.[2] Due to the lack of an automatic transformer tap changer, the Arrow IIIs cannot switch between line voltages while in service.After the North Jersey Coast Line was changed to 25 kV south of Matawan, MU service to Long Branch was replaced by push-pull trainsets only.However, the Arrow IIIs have some prominent differences, notably the two small air intake blisters (as opposed to the large humps on prior models).The large central air scoop over the center of the roof on each cab end is the final major spotting feature.The rebuild replaced the original DC propulsion system with a new solid state 3-phase AC 4-pole asynchronous propulsion system using GTO thyristor technology and VVVF inverter control that also included higher power traction motors with a total of about 375 hp per two axle truck.