Railway Insulated Rail Joints
Railway Insulated Rail Joints :- Insulated Rail Joints (IRJs) are required to join together mechanically but no electrically. they are required for the follwing purposes:
- to define the limits of jointed track circuits,
- to provide insulation between rails at S&C, necessitating track circuit transpositions,
- where transpositions are required for other purposes,
- to provide traction return isolation.
The following shell be considered relative to IRJ Provision in S&C as constrained by permanent way engineering considerations:
- IRJs adjacent to cast crossings shall be avoided wherever practicable.
- IRJs, run over in the high speed route shall be avoided as far as practicable.
- There shall be a minimum distance of 200m between chair of rail fastenings of opposite polarity/phase to reduce the probability of failures due to metallic litter, etc.
Insulated Rail Joints – Buffer Stops
Rail mounted buffer stops in track circuits areas must be fully isolated, by one of the following means:
- Provision of an insulated design of buffer stop.
- Provision of ITJs in both rails, for a double rail track circuit, or
- Provision of an IRJ in the insulated rail, for a single rail track circuit.
in order to ensure detection of the shortest vehicle, the IRJs shall be located at 4m + 0.5m from the face of the buffer stop. the position of the IRJs for friction buffer stops shall be determined from figure F8. The type of IRJ must be of a design which offers similar tensile strength to conventional steel fish plates.