staff instruments
The staff instruments in the station's safeworking room, or 'staff hut'. The small mechanical signal box is a separate building on the platform nearby, and is operated by the station employee, or by train crews when the station is unattended.
For anyone who doesn't know about it, I will try to explain electric staff working in a few paragraphs! It is a token system for single lines. On single lines there are "crossing" locations with two or more tracks, where opposing trains can 'cross' or pass each other. Between crossing locations there is only one track ("single line"), and the purpose of token working is to ensure that there is only one train at a time on that section of track, in order to avoid the possibility of collision.
In token working the driver of a train must be in possession of the correct token for the single line section. The token is inscribed with the names of the locations at each end of the section to identify it. The token gives the authority for a train to occupy that single line section, and it must be carried on the train while it is in that section.
In electric staff working, the token is rod shaped and called a staff, and there are a number of staffs for each section. The staffs are normally held within a pair of staff "instruments", one at each end of the section. The instruments are electrically connected, and when a staff is withdrawn from one of the instruments, they both become locked and no more staffs can be withdrawn. When that staff is returned to either instrument, both instruments are unlocked and another staff can then be withdrawn. This ensures that only one staff can be out of the pair of instruments at any one time, and so only one train can carry the staff and be authorised to enter the section at any time.
Phew!
staff instruments
The staff instruments in the station's safeworking room, or 'staff hut'. The small mechanical signal box is a separate building on the platform nearby, and is operated by the station employee, or by train crews when the station is unattended.
For anyone who doesn't know about it, I will try to explain electric staff working in a few paragraphs! It is a token system for single lines. On single lines there are "crossing" locations with two or more tracks, where opposing trains can 'cross' or pass each other. Between crossing locations there is only one track ("single line"), and the purpose of token working is to ensure that there is only one train at a time on that section of track, in order to avoid the possibility of collision.
In token working the driver of a train must be in possession of the correct token for the single line section. The token is inscribed with the names of the locations at each end of the section to identify it. The token gives the authority for a train to occupy that single line section, and it must be carried on the train while it is in that section.
In electric staff working, the token is rod shaped and called a staff, and there are a number of staffs for each section. The staffs are normally held within a pair of staff "instruments", one at each end of the section. The instruments are electrically connected, and when a staff is withdrawn from one of the instruments, they both become locked and no more staffs can be withdrawn. When that staff is returned to either instrument, both instruments are unlocked and another staff can then be withdrawn. This ensures that only one staff can be out of the pair of instruments at any one time, and so only one train can carry the staff and be authorised to enter the section at any time.
Phew!