This means that maintenance is NOT a 24 hour window but there is a larger crew on when the fleet is not in use (and only when there is a major issue the crew is operational during busy times). Add resources off peak and remove them from on-peak. There probably are enough workers...just shift the majority to the night shift and have them all work in unison.
There are also specific lulls in the demand (Christmas, summer, etc). In private industry these are used for significant overhauls.
A $6M vehicle is not a car that can be in the auto shop while you have a renter. It is a large capital outlay for the taxpayers that should be respected.
Private industry can target between 3-5% out of service once you have a large enough fleet. 10-20% would mean we would be fired for incompetence.
To put it back into the TTC's perspective....
There are numerous different maintenance crews. Cleaning. Running repairs. Body men. Mechanical. Electrical. All do different jobs, and not all need to have the same shifts. Cleaning and running repairs are doing mostly at night, but the body men may only need to be on duty during the day, as their jobs are more intensive and require more time, effort and equipment to do.
In transit there is also almost zero capability for sourcing extra equipment if needed on a day-by-day basis, and an absolutely zero capability when it comes to the streetcars and subways. Thus, you need to make sure that your spares ratio is high enough to cover all potential situations - not just vehicles that break down on a day-to-day basis, but also for recalls and warranty work, fitting out of new and updated systems, to name but two.
Finally, what is the average amount of time that your vehicles are on the road? From what I recall from my friends in the logistics industry, the average time on the road for each truck is something like 5 and a half hours per day, 5 days a week. A transit vehicle averages far more time in service - for the TTC's bus fleet, it's something like 13 hours a day, 6 days a week. Streetcars are something similar. That's a lot of wear-and-tear not just on the engine and transmission, but suspension and steering components, doors and windows, HVAC, etc.
Dan
Toronto, Ont.
