The GE U18B diesel-electric locomotive was introduced by GE Transportation as a branch line roadswitcher in 1973.Easy to spot due to its relatively short length — 54 ft 8 in (16.66 m) — it was the only North American locomotive powered by the 8-cylinder 7FDL engine. The Seaboard Coast Line Railroad (SCL) bought 105 U18Bs, far more than the second-best U.S. customer, the Maine Central Railroad (MEC), which ordered 10.