Caption: After meeting a Mimico - Toronto yard transfer about a mile north, the Toronto - Mimico yard transfer passes Don station beneath Queen Street. Note the yellow flag hung on the station wall. As this train order semaphore was only equipped with green and red lenses, a yellow aspect had to be created to allow trains to grab orders on the fly. Red signal with yellow flag by day, or lantern on the platform by night, permitted this operation.

Scan and editing by Jacob Patterson.