GE B23-7

The GE B23-7 entered production in late 1977 as the direct successor to General Electric's U23B, which had been manufactured from early 1968 through mid-1977. The new model represented GE's transition into its Dash 7 series, a line of locomotives that incorporated refined electrical systems, improved adhesion control, and updated cab designs compared to the preceding Universal series. The B23-7 was positioned to compete directly with the Electro-Motive Division's highly successful GP38-2, targeting railroads seeking a capable and economical four-axle road switcher in the 2,250 horsepower range. Over the course of its production run, which lasted through 1984, General Electric delivered a total of approximately 537 units to customers in the United States and Mexico. Nine domestic railroads purchased the type, and it also found buyers among Mexican carriers including Ferrocarriles Nacionales de Mexico. General Electric's Brazilian manufacturing operation assembled 13 units in December 1979 for customers including the United South Eastern Railways and the National Railways of Mexico. An additional 17 locomotives were assembled in Mexico from GE-supplied kits for Ferrocarriles Nacionales de Mexico, numbered in two separate series. General Electric also produced a ten-unit variant designated the BQ23-7 for the Seaboard Coast Line, numbered 5130 through 5139, which featured a distinctive Q-style cab with an extended nose section. Among the more notable B23-7 operators was Southern Railway, which took delivery of 54 units built to the road's own specification, featuring Southern's characteristic high short hood configuration. The Missouri Pacific Railroad participated in an important developmental chapter of the model's history when it received three modified units designated B23-7A in 1980, numbered 4667 through 4669. These locomotives used the same 12-cylinder FDL prime mover but were uprated to 3,000 horsepower, and the operational experience gained from testing them across the Missouri Pacific system contributed directly to the development of the subsequent GE B30-7A model.

The B23-7 is built around GE's FDL12 prime mover, a 12-cylinder version of the FDL engine family that GE had developed for its locomotive line. The FDL engine is a four-cycle, turbocharged design, and the 12-cylinder configuration in this application produces 2,250 horsepower, making the locomotive well suited for branch line, local freight, and secondary main line service. The locomotive rides on a B-B wheel arrangement, meaning two two-axle trucks, with DC traction motors powering each axle. At 62 feet 2 inches in length, the B23-7 is two feet longer than the U23B it replaced, a change that accommodated updates to the internal layout and equipment. The Dash 7 series as a whole benefited from improved wheel slip control and more refined load regulation compared to the Universal series, contributing to better tractive effort utilization under poor rail conditions. The experimental B23-7A variant demonstrated how the FDL12 platform could be pushed to higher output levels, producing 250 horsepower per cylinder for a total of 3,000 horsepower without changing the basic engine configuration. However, the Missouri Pacific's test units differed from standard production in lacking the Sentry wheel slip system and using different engine governors, which ultimately kept them outside the formal B30-7A classification even after Union Pacific absorbed the Missouri Pacific and renumbered the units into its roster as numbers 257 through 259. This distinction underscored how closely GE tied specific control and governor configurations to its model designations during this period.

Models by: Atlas