Driver-controlled operation

Driver-controlled operation is the operation of a train in which the driver carries out all the essential roles needed to operate the train itself. It differs from driver-only operation (DOO, also called one-person operation) in that other members of staff also work on board—for example, revenue collectors.

Currently, only around 30% of Britain's journeys are either DCO or DOO, meaning the remainder require a guard to operate and thus, if there is no available guard, the service must be cancelled. DCO means only the unavailability of a driver would lead to a cancellation of a train.