Rail vehicle having an assembly for securing an electrical external power supply connector on the rail vehicle, - in which the connector is at least partially enclosed by a housing, and the housing has a slot for receiving a catch, - in which a flap is connected to the housing via a pivot pin such that the flap can rotate between a first position and a second position, wherein, in the first position, the flap at least partially covers the connector and thus prevents access to the connector, and wherein, in the second position, the flap allows access to the connector, - in which the flap has a lock cylinder with key, wherein, in a first state of the lock cylinder, the key can be pulled out of the lock cylinder, and wherein, in a second state of the lock cylinder, the key is secured in the lock cylinder against removal, - in which the lock cylinder is designed to rotate a catch and is connected thereto, - wherein, in the first state of the lock cylinder, the catch completely engages in the slot in the housing in order to lock the flap in the first position, and - wherein, in the second state of the lock cylinder, the catch is not in engagement with the slot of the housing in order to unlock the flap in the first position and in order to allow the flap to be brought into the second position, wherein - the flap has a slot for receiving the catch, and wherein - in the first position of the flap, the slot in the flap corresponds with the slot in the housing in such a way that, in the first state of the lock cylinder, the catch completely engages in the slot in the housing and in the slot in the flap, and wherein - in the second position of the flap, the slot in the flap is designed and is arranged with respect to the slot in the housing in such a way that engagement of the catch in the slot in the housing is prevented, with the result that the lock cylinder remains in the second state, - wherein the rail vehicle has at least two of these secured connectors and the at least two lock cylinders are designed to be actuated by an identical key, - wherein, in the operative mode of the rail vehicle, only exactly one key for actuating the lock cylinders is provided for the operating personnel on the rail vehicle. - in which the connector is at least partially enclosed by a housing, and the housing has a slot for receiving a catch, - in which a flap is connected to the housing via a pivot pin such that the flap can rotate between a first position and a second position, wherein, in the first position, the flap at least partially covers the connector and thus prevents access to the connector, and wherein, in the second position, the flap allows access to the connector, - in which the flap has a lock cylinder with key, wherein, in a first state of the lock cylinder, the key can be pulled out of the lock cylinder, and wherein, in a second state of the lock cylinder, the key is secured in the lock cylinder against removal, - in which the lock cylinder is designed to rotate a catch and is connected thereto, - wherein, in the first state of the lock cylinder, the catch completely engages in the slot in the housing in order to lock the flap in the first position, and - wherein, in the second state of the lock cylinder, the catch is not in engagement with the slot of the housing in order to unlock the flap in the first position and in order to allow the flap to be brought into the second position, - the flap has a slot for receiving the catch, and wherein - in the first position of the flap, the slot in the flap corresponds with the slot in the housing in such a way that, in the first state of the lock cylinder, the catch completely engages in the slot in the housing and in the slot in the flap, and wherein - in the second position of the flap, the slot in the flap is designed and is arranged with respect to the slot in the housing in such a way that engagement of the catch in the slot in the housing is prevented, with the result that the lock cylinder remains in the second state, - wherein the rail vehicle has at least two of these secured connectors and the at least two lock cylinders are designed to be actuated by an identical key, - wherein, in the operative mode of the rail vehicle, only exactly one key for actuating the lock cylinders is provided for the operating personnel on the rail vehicle.