Control of Outlying sidings:
Sidings taking off from running lines and located between block stations known as outlying or intermediate sidings.
Minimum equipment required :
Facing Point Lock :
A gauge tie plate where steel sleepers are not provided. Facing point lock or equivalent mechanism. Plunger shall lock each switch independently.
Speed Restriction :
Speed Restriction of 50 KMPH on running lines over facing point. Where sectional speed is more than 50 kmph marker to be provided. In addition, a caution and termination indicator shall also be provided.
Points control through Block Instruments :
- The points should be controlled by the block system in use only in the case of facing points on the single line as well as in the case of double line trailing points.
- The points normally set and locked for the running line are released by token / by key interlocking boxes and electrically transmitted keys.
- At station X a token key interlocking box with a spare token locked in it and at the siding, a similar box, but with the points key locked in it are provided.
- An EKT circuit is provided between station X and the siding, a key is locked in the EKT at X and there is no key in the EKT at the siding.
- Train proceeds from X or Y with a token and is stopped at the siding and the token is exchanged for the points key on the token key interlocking box, the points key is used to unlock the points, the train then enters siding.
- The points are then reset to normal, and after ensuring that the running line is clear, the key is transmitted to X to clear the section.
- For the train to come out of siding, the guard informs X on the telephone. X obtains a token, exchanges it for the key and transmits the key to the siding.
- The key is used for unlocking the siding points, the train enters the running line, the points are reset to normal and key released from the points exchanged for the token originally deposited in the token key – interlocking box.
- The train proceeds with the token to either X or Y.
- Only one train can be dealt with in the siding at a time.
- On the double line, the block instrument cannot be restored to the normal position until the train is received at the receiving end.
- Interlocking may, however, be provided between the block instrument and the points so that the points cannot be unlocked without the block instruments being in TOL position.
- When it is necessary to clear the block section, when the train has entered the siding, the intermediate siding is worked as block station and switched out when the use of the siding is not required.
- However, where double line block instruments which provide for an occupation key to enable trains to enter block section in the right direction and return to the same station.
- The occupation key when removed locks the key in normal position.
- In such cases, the occupation key can be used for sending trains into intermediate siding and section cleared after the train is berthed in the siding.
- The train can only return to the station from which it entered into the block section traveling in the wrong