A service vehicle for operating on a rail system of a storage and retrieval grid , the service vehicle being configured for retrieving a remotely operated vehicle for service, wherein the service vehicle comprises: - a first vehicle area in which the remotely operated vehicle can be received by the service vehicle while the remotely operated vehicle is still on the rail system , and - a second vehicle area in which the remotely operated vehicle can be supported by the service vehicle for servicing, wherein the first vehicle area is configured as a vehicle pen for holding the remotely operated vehicle before entry to the second vehicle area, and wherein the first vehicle area is linked to the second vehicle area for passage of the remotely operated vehicle via the vehicle pen , characterized in that the vehicle pen comprises: - an entry barrier to regulate entry of the remotely operated vehicle into the service vehicle and the vehicle pen , and - an exit barrier on exit from the vehicle pen into the second vehicle area to regulate the passage of the remotely operated vehicle through the first vehicle area and into the second vehicle area , wherein the entry and exit barriers comprise moveable barriers, each moveable between an open position in which it allows passage of the remotely operated vehicle , and a closed position in which it restricts passage of the remotely operated vehicle , and wherein the entry and exit barriers are regulated such that the entrance barrier can be opened only when the exit barrier is closed, and vice versa. remotely operated vehicle for service, wherein the service vehicle comprises: - a first vehicle area in which the remotely operated vehicle can be received by the service vehicle while the remotely operated vehicle is still on the rail system , and - a second vehicle area in which the remotely operated vehicle can be supported by the service vehicle for servicing, - a first vehicle area in which the remotely operated vehicle can be received by the service vehicle while the remotely operated vehicle is still on the rail system , and - a second vehicle area in which the remotely operated vehicle can be supported by the service vehicle for servicing, wherein the first vehicle area is configured as a vehicle pen for holding the remotely operated vehicle before entry to the second vehicle area, and wherein the first vehicle area is linked to the second vehicle area for passage of the remotely operated vehicle via the vehicle pen , characterized in that the vehicle pen comprises: - an entry barrier to regulate entry of the remotely operated vehicle into the service vehicle and the vehicle pen , and - an exit barrier on exit from the vehicle pen into the second vehicle area to regulate the passage of the remotely operated vehicle through the first vehicle area and into the second vehicle area , - an entry barrier to regulate entry of the remotely operated vehicle into the service vehicle and the vehicle pen , and - an exit barrier on exit from the vehicle pen into the second vehicle area to regulate the passage of the remotely operated vehicle through the first vehicle area and into the second vehicle area , wherein the entry and exit barriers comprise moveable barriers, each moveable between an open position in which it allows passage of the remotely operated vehicle , and a closed position in which it restricts passage of the remotely operated vehicle , and wherein the entry and exit barriers are regulated such that the entrance barrier can be opened only when the exit barrier is closed, and vice versa. <EOS>