Sorry, at the moment it is not possible to do driver experiences, either on steam or diesel locomotives. This is something we are considering for future introduction.
In the meantime, subject to your level of mobility and availability of a suitable engine crew, you can pay £20 for a return trip to Inch Abbey in the cab of the locomotive on a public running day. This is not something that can be booked in advance, it is strictly pay on the day. This is restricted to passenger trains – footplate rides are not permitted on the diesel-hauled ECS trains at the start and end of the day. We cannot guarantee in advance that any specific locomotive (steam or diesel) will be in service.