Better question, How long did the Crusader streamliners head the Crusader route vs diesel? It seems that is being overlooked at the least, and who ran how much of the train by title , where and when, is another thread for after the day the streamliner ended is accounted for I'd think...that is the subject once settled is most on topic imo.
From the American Rails website:
"Locomotives No. 117 and No.118 were both kept at the Reading's facilities in Philadelphia. One engine would pull the morning Philadelphia to Jersey City round trip and the other engine would later pull the afternoon round trip.
In 1948, two EMD FP7A diesel-electric engines replaced the two streamlined steam locomotives. Both steam engines had their streamlining removed and were placed on other assignments. In 1950 the two Pacifics were retired and replaced by more EMD FP7A diesels."
Rusty