A while back I posted a pic of the C.P. Roundhouse in Vancouver and ask what the track going around it was for. The always knowledgeable people on this forum suggested it was a balloon track used for turning Passenger trains. Well I came across this photo of the track in action.
Also if you feel like looking at some old C.P. pics here’s a few to look at.
http://www.rr-fallenflags.org/cp/cp.html
Brent