LOW ADHESION Flashcards
What is low adhesion?
It is when the train experiences limited grip between the train wheels and railhead.
What are the causes of low adhesion?
Leaf fall
Railhead contamination (grease, rust, oil)
Rain fall
What part of the train does low adhesion have a significant effect on?
It affects the acceleration and deceleration of the train, which greatly reduces the train’s ability to stop at stations and signals.
What kind of damage does low adhesion cause to the train?
It damages the wheel profile of the train.
Levels of rail adhesion (reportable), what are the three categories?
Good - adhesion conditions are good. No action is required.
Expected - no worse than expected for the location and environmental conditions.
Reportable - is worse than expected for the location and environmental conditions.
Would you need to report expected low adhesion levels?
No, you don’t.
How would a signaller notify you of ‘reportable’ low adhesion?
Through a general broadcast or contacting you directly.
When might you be asked to carry out a controlled test stop?
When a low adhesion is reported rail has been inspected and nothing unusual has been found
When the line has been treated
When 30 minutes or more have passed since the report was made
How would you carry out a controlled test stop?
Brake the train in a way that you would normally for expected conditions at the location, rather than the way you would brake for ‘reportable’ rail adhesion levels.
What must you tell the signaller after the controlled test stop?
The results of the test
If the rail adhesion level should still be considered ‘reportable’
When would you experience wheel slip?
When the train is taking power.
When would you experience a wheel slide?
When the train is braking.
What are some low adhesion risks (what does it affect)? 10 answers
Service punctuality Traction Signals passed at danger Station overruns Collisions Damage to train wheels Damage to rails Failure to activate track circuits Reduces the trains ability to start, accelerate and maintain speed
How could you mitigate/manage low adhesion risks?
Using manual sander Controlled test stops Reporting low adhesion levels Install WSP on trains Drivers to check low adhesion boards On-train safety systems
When does low adhesion occur?
All year around but specifically worse in Autumn.
