Conrail EMD SD40-2 6423, paired with SD40 6255 and a third unit, handles a manifest at Donohoe, Pennsylvania on April 23, 1983. David V. Leonard is the photographer. The SD40-2 has been judged Conrail's most reliable and cost-efficient heavy freight locomotive. No. 6423 was delivered in 1977 with Conrail's first order for the SD40-2; it became Norfolk Southern 3368 with the 1998 partition of Conrail. Unit 6255 was delivered to Penn Central with that number in 1970; in 1996 Conrail renumbered it to 0808 so that a new GE C40-8W could assume its number in the 6200 series. The later history of 6255 is uncertain; it may have passed to Helm Leasing, since photos show it operating in yard service in Iowa in 1995.