SD60M's fit the bill for new power in 1992 when Conrail ordered 74 SD60M's. Within the SD60M class is one main spotting difference; marker lights. 5500-5514 were built with FRA flush mounted marker lights until a study done within Conrail declared the protruding lights caused a safety concern. Subsequently, the remaining order, 5515-5574 were recessed.
The units were built with a 2 piece front windshield and 4 piece side windows without sun visors. The side windows are built on an easy slide track design and combined with the tinted glass provide superior crew comfort. Conrail's SD60Ms were numbered in the 5500-5574 series, with one exception: 5544.