Northbound Extra freight in the siding at McKinley Park. GP35’s 2503 & 2502 sandwich F7B’s 1507,1515,1505 & 1501. This train brings questions in my mind, it is cleared with the number of the trailing unit, in this case as the Extra 2502 North. It was not the only train I saw cleared that way , and would think there would be a potential for misidentification . This was two years prior to going to work for a railroad and didn’t give it much thought at the time. 8/4/75.