General Electric?s ?Dash 7? locomotive line was introduced as a replacement for the older ?Universal-Series? of the 60s and early 70s. ?Dash 7? series improvements included increased fuel efficiency, tractive effort and reliability. The B23-7 was a direct replacement for the 2,250HP U23B model. The first units were produced for Conrail in September, 1977 (ironically, 3 months after the last U23B was delivered to Conrail). Production continued through 1984, with a total of 535 units built. Conrail was the largest purchaser of the model, with a total fleet of 141 units. Several features distinguished B23-7s from predecessor models. The long hood stepped outward in the area of the exhaust stack to accommodate a relocated oil cooler. In addition, the frame was 2 feet longer than that of the U23B. An FB-2 style truck was offered as standard equipment on B23-7s, but some railroads opted to use ?trade-in? trucks. Therefore, AAR type B and Blomberg trucks could be found on some models. The six power assembly doors (located near the center of the long hood) indicated that the B23-7 was powered by a 12-cylinder GE FDL engine. There were three distinct ?phases? to B23-7 production. Our model is of a ?phase 1? unit with a 36?2? wheel base. Phase 1 production lasted through the spring of 1979. Features: The Atlas B23-7 locomotive model includes such optional/road name specific details as: ? Pilots with and without anti-climber ? Cab headlights or low-nose headlights ? Cab with 4 or 2 side windows ? Bell mounted under the sill or on the long hood ? FB-2, AAR type B, or Blomberg truck side-frames used where appropriate per road name Additional Features: -Separately-applied scale detail parts include: windshield wipers, metal grab irons, coupler cut levers, multiple-unit hoses, snow plow, train line hoses, fine scale handrails, and more! -See through step detail on sill -Etched metal radiator grilles -Painted crew members -Factory-equipped with AccuMate knuckle couplers -Coupler pocket designed to accept AccuMate Proto-couplers -Five-pole skewed armature motor with dual flywheels for optimum performance at all speeds -Directional lighting Atlas Master? Series Silver Additional Features: (Item #s 8000-8024) -NMRA 8-pin plug for DCC (Decoder-ready) Atlas Master? Series Gold Additional Features: (Item #s 8100-8124) -Electronic Dual-Mode? Decoder (e-DMD) that allows your locomotive to run in DCC or traditional DC QSI? Quantum System? Features Including: (Atlas Master Series Gold locomotives only) -Dual speaker system -Authentic diesel engine sounds -Squealing brakes -Doppler effect -Air let-off in neutral -Coupler impact sounds when operated with DCC -Helper mode that mutes the whistle and bell for double heading -And more!