It hasn't been operated in a LONG time. IAH-YUL has been a route I've flown regularly since 2002 and I've always had to connect at CLE/EWR/DTW/MSP/YYZ.

I don't see mainline hitting YUL for a long time, either. YYZ has lots of business traffic and it only gets one daily 735. YUL is a marginal station, mostly leisure traffic in my experience. I'm surprised that AA maintains MD80 service to DFW, but AA poached a lot of CP FFs after their collapse.