July 2012 in Network Rail and Suppliers
The line speed when leaving Kingsbury junction heading towards Whitacre junction is 45mph, which is then reduced to 25mph at Whitacre junction. However, recently a 40mph permissible speed board has been erected about 100 yards before the 25mph permissible speed board. The reporter is concerned that 100 yards is not a sufficient braking distance to be able to reduce speed from 40mph to 25mph. It is felt that this could lead to incidents of speeding. The reporter believes that the distance between the two permissible speed boards should be 200 yards.
The reporter is not aware of any standards that stipulate what the distance should be between permissible speed boards in non-emergency situations.
Could Network Rail:
Response from Network Rail
Network Rail would like to thank the reporter for bringing their concerns to our attention.
Could Network Rail comment on how the distance between the permissible speed boards is decided, with reference to safe braking distance?
The provision of speed boards and the associated advance warning indicators are specified within theRailway Group Standard GK/RT0075 'Lineside Signal Spacing and Speed Signage'. This standard requires speed boards to be positioned 'where the change of permissible speed occurs'. Advance warning indicators are used to give Drivers additional warning of a speed restriction ahead, and are only required to be provided if the permissible speed on the approach is 60 mph or greater and the required speed reduction is one-third or more.
Could Network Rail consider increasing the distance between the 40mph and 25mph boards on the approach to Whitacre junction?
The 40 mph speed restriction is not intended to give the Driver
a warning of the 25 mph speed restriction for Whitacre junction.
The 40 mph speed restriction has been provided due to signal
spacing constraints ahead of the junction. Advance warning
indicators are required to be provided to warn the Drivers of the
speed restrictions ahead. However at this site the approach speed
is 45 mph and therefore there is no requirement to provide an
advance warning indicator.
The arrangements noted by the reporter were commissioned recently by the Water Orton Re-signalling Project. The project team have noted that prior to the commissioning an existing advance warning indicator was provided at this location for the previous speed restrictions at the site. The project has reviewed the new arrangements and from the Drivers point of view the warning of the 25 mph speed restriction has been removed.
Discussions have been held with the Signalling Designers and a representative of the Major Scheme Review Panel who accept the design of all Network Rails' major re-signalling schemes. It was considered that an additional advance warning indicator at this site would cause an unwanted distraction to the Driver and would reduce the effectiveness of the Automatic Warning System(AWS) as advance warning indicators are provided with a permanent AWS magnet.
However, the project team do believe that the removal of the advance warning indicators could have been communicated better within the Driver training material. The project team have also reviewed other areas within the project where this situation occurs. It is the intention of the project team to issue a briefing note to the relevant train operating companies warning them of the loss of the advance warning indicators at these sites. This issue will also be passed on to the producers of the Driver training material so that for future projects when an advance warning indicator is removed or significantly relocated, it is brought to the attention of the relevant Drivers prior to the commissioning of the new signalling system.