Each individual depot are responsible for their own maintenance budgets? I'm not doubting for a minute that that's true, but I really can't see the logic in this one. Choosing not to spend money on a bus because it might get transferred for service at another depot is a ludicrous way to run a business.

You wouldn't get the commercial team refusing to market a service, for fear that those boards are transferred to a different depot... why shouldn't it be the same for engineering...?