It appears that the MILW 'torpedo tube' passenger GP9's were delivered in the summer of 1954 - Well before the 1955 City paint scheme. They were renumbered sometime around 1959 in the general diesel renumbering to the 200 series. From my picture records, it appears that 201/203/205 were repainted in the UP 'Armour Yellow' paint scheme. They were renumbered again to the 800 series and spent a lot of their last years in Chicago terminal service(hump or transfer engines).
There are pictures in the early 60's on yellow passenger GP's puling the 'Chippewa' passenger train. I have also seen pictures of them on the Pacific Extension pulling National Guard extras to camp.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin