Last year the photographer got some close ups of ES6 #9138 moving a reefer to the ice rack. Purchased in 1945, the ES6 was not the first diesel the Pennsy bought, but it was the first diesel it bought in large numbers. The EMD 567 600hp V6 in the SW-1 version was an improvement over the Winton 201-A 600hp straight 8 in the earlier SW.
The ES6 (EMD SW-1) is MTH, reefer is Atlas.