Certain types of inspections ("Standard" Inspections) are only done during the day and take most of the day to complete. These are pretty comprehensive and involve checking just about everything. There are only a few cars done each day as the fleet rotates through. There are more frequent night time inspections, known as "Pit" inspections, which focus underneath the cars, the traction system, running gear and brakes (in the case of CLRVs/ALRVs/PCCs. I'd assume that this would be similar for the Flexity cars as well). I think there are more cars done each night in Pit inspections so they cycle through the fleet more quickly.
Speculation here, it may also be that the Flexity cars also have a more frequent inspection cycle since they are new and they may want to see how certain equipment is holding up to daily wear and tear.
Repairs are done on any shift, except for large jobs, which may be done on a single shift so that the same technicians do the work. Obviously major repairs are done at Hillcrest rather than at the carhouses. Like any other vehicle, some electrical repairs may require quite a bit of detective work to figure out where a malfunction is occurring and the underlying cause, while other repairs are simple swap outs of defective components.
A few cars also receive thorough ceiling-to-floor interior washes during the day (usually ones that had Standard inspections the day before).
The number of cars tied up during the day for this work isn't that big, most of the inactive cars are sitting in the yard.
Carhouse operations are actually quite interesting when you see how much is happening on a daily cycle. You never get to see all this during the brief Doors Open events.
