While the G22 was delivered without a turbocharger for easy maintenance, the GT22 received a turbocharger and correspondingly higher output. Here, too, different variants were created with four or six traction motors, different track gauges and with or without train heating. On request, the locomotive was designed to be particularly light. Soon the more modern generation of electronics was installed, called “Dash 2” by EMD. Individual variants, such as the GT22HW-2, were only built for a single customer. In this case it was the Yugoslav Railways, which ran the locomotives as the series 645. 