I agree with Davey that the X21/22 needs replacements for 7501-9, however I don't think that they should then go onto a service that has newer stock currently. I think the best bet for them would be to send them onto a service that currently has old stock, but is profitable (if such a route exists). Either way, most of them are shot and only any real use on a local town/city service, not an "express" route.