Also, once the overhead was up, nation was in the middle of the various fiscal events known as the Great Depression. Demand for services down. So it might have been cheaper overall to use what you had, even if it means doubeheading.
With the 610 test, thete were places it could not go because of clearance issues. Could this also be a reason for no 4-8-4's? Or did not help in the engineering of the duplex?
