I think you mean the DRS-6-6-1500. This loco was the predecessor to the AS-616. Baldwin manufactured 82 DRS-6-6-1500s.
Stewart could use the AS-616 chassis to do a DRS-6-6-1500. The carbody is somewhat similar too, but I believe the radiator grille is lower down and the corners of the hood are sharper like a DRS-4-4-1000.