HO GP39-2 Locomotive, CSX / YN3 #4311 Overview
CSX purchased 20 ex-Reading/D&H GP39-2's in the late 1980's. They operate alongside CSX's other EMD GP's providing power for locals, haulers, and road switching assignments. Most of the fleet can still be seen operating today.
In the decade between 1974 and 1984, EMD produced the GP39-2 for seven North American railroads. The basic design followed most four axle road diesel switchers for the time. Borrowing improvements from the GP38-2 and GP40-2 designs, this mid-horsepower road switcher utilized a turbocharged 12-cylinder EMD 645E3 diesel engine for its prime mover. With 4 fewer cylinders, the smaller engine provided a distinctive long hood on the phase II and phase III bodies, where the clean room/engine compartment doors were set back from the cab further than predecessor locomotives.
Sensitivity to fuel economy in the 1970s justified the GP39-2 in the locomotive market. It also laid the ground work for EMD to start exploring locomotive designs that utilize engines with larger piston displacement yet possess fewer cylinders. This approach has become the foundation to modern locomotive technology.