The term Isolation denotes the condition in which line for a particular movement is separated from all adjoining line connected to it in such a manner that the isolated lines cannot be fouled or interfered with by any movement-taking place on the adjoining lines.
Rules regarding Isolation :
- A line which train movements at speeds higher than 50 kmph are permitted, the line should be isolated from all connected lines.
- Passenger lines should be isolated from all connected lines and sidings, whatever the speed may be.
Isolation of goods reception lines from sidings is considered desirable
- To maintain safety in thorough running, points and trap sidings should not be inserted in the main or through lines.
Exceptions to this rule, may be adopted with the special sanction of CRS is obtained are :
- Where other means cannot be adopted, to permit simultaneous reception of trains on single line sections.
- To trap vehicles running away from a station
- To avoid trains entering from block section due to the heavy falling gradient.
Methods of Isolation:
- Connecting to another line or a siding
- Provision of short dead end sliding (Vehicles should not be stabled on this siding)
- Provision of traps, derailing switches (inexpensive, popular dependable)
- Long dead-end siding with trap (Vehicles can be stabled on this siding)
- Provision of sand humps