Joe-
I am researching the early days of the Aurora Branch, Chicago & Aurora and Chicago, Burlington & Quincy and have to wonder about your statement (presumably about Mendota). I am not exactly sure about the dates of construction of the IC line to Galena, but from trade journal reports of the time I don’t think the IC made it through the area that became Mendota much before the CB&Q reached the area. In fact, some reports suggest that the IC had not named the town nor laid it out before the Q reached that point. I will have to delve into the history of the IC to find out how long it was before the IC made it to Mendota. I do know that the line to Galena was not completed until well after the Aurora Branch was in service as the IC from Freeport to Dunleith (East Dubuque) was operated by the G&CU and their trains operated into Chicago over the G&CU and this lasted for a couple of years.
Charlie Vlk
But by 1945, the IC had been in town ~90 years and the CBQ ~60 years, so a lot of things could have changed.