It's near to some points and there is a siding / loop close to the crash site, so it could be broken points, but it's far too early to say. They pulled out the data recorder yesterday, but I doubt that will have the answer as it's a straight section of track, unless speed over the points was an issue - ie if the train was routed over the points onto a different line.
They're LRC stock from Bombardier, I think. Lightweight tilting stock that originally had their own dedicated locos, but now use EMD locos. That one, I find, was F40PH no.6444.
They do seem rather accident prone: Originally delivered as nos. 6400-6458; 6447 wrecked in 1997 Biggar, SK derailment; 6423 was wrecked in 1999 in Chatham, ON collision; 6450 was wrecked at Miramichi, NB in 2000; 6400 was wrecked at St-Charles, QC in 2010; 6422 and 6430 have also been wrecked; all 6 locomotives were written off from the roster. 6444 was involved in the Burlington, ON accident on February 26th 2012. http://en.wikipedia.org/wiki/Via_Rail
The F40PH is the ubiquitous American locomotive though, they're used throughout the continent. I don't think they're accident prone, more that they were basically the entire VIA fleet until the Genesis came along.
The LRC was basically Canada's take on the APT but laid out more like an HST with power cars. In practise they ended up running as short loco-hauled rakes but they were meant to function as double-ended sets and as Schnellzug says they're now just used as regular hauled stock alongside Nightstar/Renaissance on the Quebec-Windsor corridor and the more typical American-style silver coaches on the transcontinental services.