March 2018 Rule Book Changes: Poor Adhesion and When to Report it

Poor adhesion can happen anywhere, anytime – it doesn’t have to be down to autumn leaves, it could be down to contamination on the rails, the weather, and some locations will be more prone to problems than others.

When drivers expect poor adhesion, they can adopt well-practised techniques as described in their Professional Driving Policies to compensate, but when it’s unanticipated, it can unsettle even the most experienced drivers. 

The Rule Book requires train drivers to report poor adhesion to the signaller, but the terms used up to now have led to some confusion and inconsistency about what and when to report.

An industry survey confirmed this – the Adhesion Working Group, which includes Network Rail and train and freight operators, surveyed over 500 drivers, and confirmed there is ambiguity – drivers do not have a confident or consistent view of how to report.

New ways to describe adhesion conditions

Changes published in the Rule Book in March 2018 are set to make it easier for train drivers to report adhesion issues, by simplifying the terms used.  This makes it much clearer about the scenarios where train drivers need to report adhesion issues to the signallers.

Train drivers and signallers in particular need to be aware of the new terms, so that adhesion issues can be reported and acted upon consistently.
There are now three terms to use:

  • Good
  • Expected
  • Reportable

If conditions are good, there are no adhesion issues, and as a driver you are experiencing no problems, so there’s nothing to report.

If conditions are expected, you may be experiencing some issues with adhesion, but these won’t be a surprise – possibly because the conditions are wet so you know you’ll be using more sand, or because the section of the line is known to have adhesion problems and you are already prepared to adapt your driving technique in response.   In other words, expected is what you would expect for the situation, and the driver behind you won’t be facing any surprises.

If conditions are reportable, you will be experiencing the unexpected – poor adhesion to a point that has come as a surprise and you as a driver will feel you needed to take action beyond what was expected for the conditions or the location, and something that could very well likely surprise the driver following you.  It’s in this situation that you would make a report to the signaller.

Table describing low adhesion conditions

Using pre-recorded GSM-R broadcasts

Changes to the Rule Book also unlock the opportunity to take fuller advantage of GSM-R cab-to-shore communication to keep trains moving.

Where a driver reports reportable adhesion problems, the signaller can potentially set up a pre-recorded broadcast to drivers via the GSM-R.  Drivers approaching locations where unanticipated, poor adhesion has been reported can be alerted on-the-move by the automated message, and acknowledge it by pressing the ST button on the GSM-R panel, avoiding the need for the signaller to bring drivers to a halt to inform them.

Drivers and signallers should use the 'Acknowledge (safety) broadcast calls' arrangements shown in RS523 GSM-R Handbook.


Ensuring the signallers are made aware of unanticipated problems is at the nub of this change.

The change will benefit the whole railway – as now the infrastructure manager will have much more focussed and targeted intelligence about where adhesion problems are, and that means effective action can be taken to manage the issues and make life easier for drivers and on-board staff – ultimately benefiting passengers and freight customers with improved safety and reliability of service.

Using pre-broadcast messages on the GSM-R could also help keep trains moving, avoiding delays.

What next?

If you are a driver or a signaller, make sure you are fully briefed on these changes to the rules so you know when to report poor adhesion, and what needs to be done in response.

  • Check you’ve updated your Rule Book on your app or hard copy, and familiarise yourself with section 28 of Module TW1 Preparation and movement of trains.
  • If you are a driver, stay up to date with your professional driving policy.
  • We have prepared a Powerpoint slide deck to help support safety briefings on this change to the Rule Book.
  • You can also download this page as a 4-page pdf brochure – get in touch with RSSB if you would like printed copies.

For more information, talk to your line manager or contact RSSB.


What poor adhesion is and when to report it
Briefing note - What poor adhesion is and when to report it
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Glen Jones
Tel: 020 3142 5624
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