The class DP1b’s (ILW model eco-640/56f/gp) are mechanically the same as the base DP1 class, but have platforms at both ends of the units; these units were designed as freight locomotives from the start (so no HEP components.) They were made for trains that originated or terminated at Washington’s Potomac Yard, so the units are slightly narrower to fit through the old PRR B&P tunnel.

They only saw use on the NW Corridor for a few years before traffic dried up south of Baltimore – when Potomac Yard was decommissioned two tracks were left for the D&H to interchange on, but after Conrail was split between CSX & Norfolk Southern those railroads stopped interchanging there, leaving the D&H with trackage rights to nowhere and no need to operate these locomotives on their rapidly electrifying railroad..

These days they are used for through traffic on the B&Q/LT&L/OC/OVR/HC/ALSO mainline between Sault Ste Marie, Ontario & St John, NB.

All of them are in service.