The GP15-1 was a somewhat unique locomotive. It was offered by EMD as a competitor not to another manufacturer's product line, but to railroads own rebuilding of older Geeps. Conrail's fleet of 100 of these lightweight road switchers arrived numbered in the 1600 series in 1979.
These units could be found system wide in use in their intended role as light road switchers working various locals both singly and in multiple unit lashups.
A lashup of 5 Conrail four axle units, lead by a GP15-1 hauls a unit coal train toward the export piers in Baltimore.
The Conrail Bottle train at Dolton, Il. You could feel the heat as this train passed you.
Conrail GP15-1 1644, SW1500 9595 and GP38-2 7874 relaxing by the shores of Lake Lansdale (aka the SEPTA parking lot).
The early 80s were a strange time on the Pittsburgh Line. Here a pair of light road units provide assistance up the hill, shoving behind two different cabooses.