Which set had locked wheels and where is it now? Was this a recent thing or the one that was stopped temporarily in Sarnia?
Re: allocation of Venture sets.- as Paul has already noted, it's not as if each set stays captive between one pair of Corridor cities. That would be a lot easier, and possibly allow better allocation of equipment based on passenger loads, but it doesn't readily allow for servicing nor the need for VIA (thanks to MX) to use Union Station tracks as run-through tracks for many VIA Corridor trains - much like GO trains do from Lakeshore West to East, I suppose.
Currently, Ventures run through from Sarnia-Toronto-Ottawa, Montreal-Ottawa-Sarnia, Ottawa-Toronto-Ottawa, Montreal-Quebec-Montreal, and even Montreal-Toronto-Windsor each day, mostly two runs per day but occasionally three! This seems to be what allows VIA to run with so few sets of equipment of any kind, once-a-week trips for maintenance, and they've had to rearrange their rotation due to unacceptable delays throwing it off, due to CN's crossing speed reductions. We're also still waiting for the TMC servicing building to be complete, and in a way it's already obsolete as neither of the augmented eight-unit sets will fit inside.
And slowdowns on the CN Kingston Sub are actually 45 mph, not 55 mph. Slower, longer trips!!!