Insulated Rail Joints,Insulated Rail Joints Buffer Stops
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.