Caption: MLW RS-23 CP 8019 is at least the third unit on the afternoon freight returning to Montreal from Trois-Rivieres (since AlCO FB unit 4408 has no cab!). 4-axle power was typical on this run, most often 3 or 4 MLW units with an occasional leading GP-35 or trailing F-unit. They could have been scraping the bottom of the barrel this day in assigning an RS-23, unless it was working its way back to Montreal for maintenance. CP 8019 was not a regular in T-R yard as I recall.
Looks like the engineer has just throttled up to get the train started. Much of the traffic was newsprint boxcars loaded at the local paper mills.