Cherry/Sumach is back in service now according to Brad Ross in twitter.
If it's just the suficial concrete, they could probably fix easily enough in the middle of the night, or middle of the day when eveything has stopped coming out of the yard.
But if it's a more severe structural issue. that requires them to dig up Leslie, I don't see how it's going to get fixed, as I don't see how they cut off access to Leslie Barns for a week or so.
They've kind of dug themselves into a hole, with only the single entrance in and out of Leslie Yard. Without a back door up Knox, or along Commissioners to Cherry. I'm not sure how they thought they'd be dealing with the inevitable rebuild on Leslie ... perhaps they thought it would be 25 years in the future rather than 5, by which point the track on Commissioners would be complete.