Leary has to go.....there's no doubt about that.
But to attribute this as a "failing under his watch" is pretty unfair. Rails crack - that's just a fact of life. And to make it worse, it is extremely difficult to detect where a crack may occur or if it may propagate into a full blown broken rail. In most cases, a cracked or broken rail can be traversed at a low speed indefinitely until it's possible to effect a repair when the system is closed.
When that crack happens at a switch point, on the other hand, it is a far more tricky thing to deal with. You can't have trains rolling over it a low speed, because it a much smaller piece that isn't secured in the same manner as a normal rail. And worse, it was a switch that is not built to the standard design(s) that the majority of the system is built to. There are some spare parts for those, but it's not practical to have a whole spare switch lying around when you are only using it in one or two places on the system. So, it takes a fair amount of time to prep a new piece of rail to replace the broken one.
Now, if we had found out that the TTC's rail milling machine was broken, and it was going to take days to make the repair? Yeah, we could put the blame on Leary for that. But that wasn't the case here.
Dan