Stress Free Sunday

I’m back with a text wall! This week I’ve been back in the training centre doing my Level 3 stressing course, and I’ve been out stressing some S&C assets.

Stressing is the act of tensioning rails to a temperature that allows for optimal expansion and contraction while minimising the risk of buckling (referred to as the Stress Free Temperature, SFT) – in the UK, that temperature is deemed to be 27 degrees for now based on the average temperatures faced throughout the year. Stressing can be achieved using hydraulic tensors or naturally (if competent).
There’s 3 different competences associated with undertaking stressing works:

  • Level 1 – allows you to restore stress in lengths of plain line rail up to 36m (putting back the same stress that was already in the rail)
  • Level 2 – covers the above, as well as restoring and undertaking stressing works on plain line lengths greater than 36m
  • Level 3 – All of the above, but inclusive of S&C assets and allows for the use of the natural stressing method.

I’ve held Level 1&2 for a number of years but it’s the first time I’ve been out stressing for a while, so this weekend served as both a good way to get back into the rhythm of carrying out the work on site and getting mentored on the new elements of the job I’ve learnt on the Level 3 training course.

S&C assets have strict sequences that have to be adhered to if they require stressing, in order to prevent deforming the asset and potentially misaligning the switches. We had three stress pulls to carry out, with the rails directly in front of the switch toes stressed first, followed by the stock rails on both the through and turnout legs and finally the rails behind the crossing.

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