D&IR Indianhead logo, used from 1910 to 1920's. Application to equipment is uncertain, but likely applied as white on black on locomotives, white on brown on freight cars, and black on yellow on reefers and cabooses. Not known to have been applied to passenger equipment. Passenger cars of all three companies were lettered in gold on Pullman green, text only.
D&IR Octagon logo, used from 1920's to the merger in 1937. Applied as white on locomotive tenders, cabs, and dark painted freight cars. Applied in black to reefers. Unknown if applied to cabooses. Not applied to passenger equipment.
DM&N Round logo, used from 1910 to the merger in 1937. Color applications same as D&IR as above, except known to be applied in black to cabooses.
DM&IR Safety First logo, used from 1937 to present. In the steam and early diesel era, applied as white on black on steam locomotives, white on brown on freight cars, and black on yellow on reefers and cabooses. Not known to have been applied to passenger equipment except the RDC1 Budd car as black on silver. In later diesel era, applied in white to some brown ore cars, in yellow on any maroon background, and in maroon on any yellow background.
DM&IR Banner logo, version 1, used from 1941 to the end of steam (1962). Applied in silver in large size to Yellowstone tenders, and in white in smaller size to 0-10-2 Union-type tenders. The above is from a photo of a Yellowstone tender.
DM&IR Banner logo, version 2, used from 1953 to 1965. Applied in black to the yellow stripe on EMD SW-9 switch engines. Very similar to the Yellowstone, but lacking the round herald in the enter.
DM&IR 3-color logo, used from 1953 to present. Applied as a Scotchlite decal to diesel locomotives, cabooses, MOW passenger equipment, some freight equipment and over-the-road vehicles (trucks and vans). Also applied to the ends of the RDC1 Budd car.
DM&IR Arrowhead logo, used from 1972 to present. Applied as a Scotchlite decal in yellow to diesel locomotives, MOW and OTR vehicles. Also applied to some steel bay window cabooses in maroon with yellow text, and to 3-bay ACF covered hoppers in maroon with yellow text. Currently being applied to OTR vehicles in yellow with maroon lettering, and to side dump cars in black on white background.