In the late 1970s, the Delaware & Hudson started yeeting their still-large fleet of 244-equipped locomotives. But a fistful of RS-3s had their 244s dealt with in the tradition of the TdM shops (but not by shipping them to ILW; instead they were sent to Boise, Idaho to be rebuilt into MK TE56-4As) of yanking the 244 and wedging a 251 into the now-empty engine compartment.

Some of the units were repainted into various experimental schemes, but by the mid 2010s they had all gone back to their original d&h paint schemes (including 506’s bicentennial paint.