It was done in the paper documents days and might not have been digitized. In addition, it was filed with the Interstate Commerce Commission, which no longer exists. I don't believe that all documents from the I.C.C. were transferred to the Dept. of Transportation. I know that most of what was in the old I.C.C. library was transferred to someplace in Colorado - the University of Denver-I think. So, you might see whether my memory serves me and the University of Denver in fact has the old I.C.C. library documents, then see if it contains a copy of the applications in question.
Robert