I'm not familiar with the Durham Transit system/frequency(ies), but the likelihood is that a US scanner will work in Canada. There is very very little difference in the US and Canadian scanner/radio market, small enough that there's no company that I know of that makes a specifically Canadian scanner. The last 3 or 4 (or more) scanners that I have purchased have all come to me from the States and do everything fine - with very few problems.
The only things I've noticed are we have a different spacing/step rate in our VHF High bandsplit than the US does (I forget what they use, but it's 12.5, 7.5, or 6.25; one of those - and we use generally 5 khz splits). This is easily handled by any scanner, but it may default to the US spacing - not a problem to fix.
The other problem is pretty much on every scanner built, to my knowledge, and you may not even have a system near you that suffers the same fate. There's a system here in Alberta with a bizarro channel structure, which is 0.125 (IIRC) mhz off the American standard. This system cannot be scanned with a trunktracker because when the system tells a radio to go to channel xyz, the radio actually goes to xyz+0.125.
Sorry for the rambling response... the short of it is, you should have no problems getting a US scanner to work in Canada.
