SP 4600
This loco was built as EME 1600 as the "cow" unit of the demonstrator TR6 set in 11/1950 with EMD construction number 13549. As built, she featured a drawbar connection to the "calf" half of the set, EMD 1600A , which was eventually replaced with regular coupler, dual cab controls and mu capability. SP purchased the demonstrator pair on 04/25/1951. She was assigned number SP 4600.
She was assigned number SP 1100 in the 1965 system renumbering.