But presumably without said depot the only other places to maintain the Mk 5As would be with the Mark 5 Sleeper Stock either in Scotland or London.
Scarborough is the lightest of maintenance - just refuelling and toliet discharge.
The primary depot is Longsight International - Scarborough is a lower level of depot - the point being made is that if only 802s had been procured, a separate depot at Scarborough would not have been needed because they could have been accommodated at Doncaster. No depot was needed at Scarborough for 185s.
It is a strange question, there has been a refuelling point for class 185s for years at the other TPE coastal terminus in Cleethorpes. I am not quite sure how far a class 185 can go before it needs refuelling, but the extra length and weight of the 68 and 5 x Mk5a carriages might have deemed the new Scarborough depot a necessity.
Hull Trains have their units serviced at Bounds Green, not Doncaster. I guess it is up to Hitachi as to how to best balance their servicing schedules against capacity of their depots. In the all 802 situation, I don't think they would need a depot at Scarborough.
I note, however, that TPE having a Scarborough depot is good for the workforce they have recruited there.
I would imagine that a class 802 unit is considerably more frugal on fuel than the the Mk5a combo, both of which contain 5 carriages. The depot seems more like a vanity project and a very costly one too, not only for the construction of the depot, but also the expense of demolishing half of the Washbeck excursion platform and relaying the adjacent track between the station and the depot, in order to provide safe clearance between the excursion lines and the running line.
Besides the work force employed in the creation of the depot, how many people actually work there now? I would have thought a security guard was essential to deter the local graffiti 'artists'.