9v and Power Functions Hybrid? I am building a train layout and I am running some of my track through a tunnel. I would like to know if I could hook up a 9v train motor at the opposite end of my train. The front will use Power Functions for the motor. Will this work together in case my IR receiver loses communication to the controller and at the same time run at the same exact speed? Is there an alternative?
I'm not so sure using 9V will be usefull ?

My son has a PF cargo train in his room, when he turns it on, it goes, ok.

but even if my son goes downstair to get a cookie while he still has the PF emitter in his hand, then train still runs !

According to me, PF infrared link is used only when you wish to change speed setting, so if you don't plan to slow down your train in the tunnel, you are ok.