Ever since the very beginning of railway traffic, one of the foremost tasks has been to ensure traffic safety. Staff instrument was one of the first devices to serve this purpose and help control traffic between at least two stations. The purpose of the instrument was to eliminate the possibility of two trains entering the same section at the same time, because the driver could enter a section only after receiving the staff. The staffs were handed over by the station ‘conductor’, the station master, who, after contacting the station master at the previous station, handed over the staff to the driver, that way giving him permission to enter the respective section. Thus, train traffic was organised similarly to a relay race where runners take turns to perform their leg of the race after receiving the staff.