Between the 16th and 19th of July 2022, the UK experienced an unprecedented heatwave with temperatures reported by the Met Office in excess of 35°C throughout England and parts of Wales. The 18th and 19th of July saw rail services severely disrupted due to the extreme weather conditions.

Risks are created in extreme temperatures which impact trains’ safe operation, such as track buckling and problems with signalling equipment. Network Rail has an operational procedure NOP 3.17 ‘Weather Arrangements’ which provides instructions for controlling risks brought about by extreme weather.

The heatwave on the 18th and 19th of July saw Network Rail jump to action imposing blanket emergency speed restrictions for many lines, these kinds of restrictions are precautionary speed restrictions actioned across a large area without the installation of speed restriction warning signs.

Rail Operating Centres saw staff issued with forms where necessary which are also known as late notices and provide information pertinent to the speed restriction, the areas affected and the train operating companies which run services in the affected area. The notices provided detailed specific speed restrictions as well as geographical limits and the times they were to be put in place.

All of the train operating companies followed their own internal processes in order to provide the information to drivers. The process of supplying the relevant detail was varied across the train operating companies and saw some post copies of the forms at drivers’ booking-on points whilst others provided personal copies of the notices to every driver either electronically or on paper.

A number of incidents were recorded over the 18th and 19th of July and saw a number of the blanket emergency speed restrictions not carried out as follows:

On the 18th of July 2022

• At 12.30 hrs, the driver of the 07.10 Penzance to Paddington service travelled at speeds of up to 125mph through 60mph blanket emergency speed restrictions. The restrictions have been put in place between Bristol and Swindon for Network Rail’s Western Route. The route had seen a diversion put in place, however, this was also subject to the same speed restrictions. The driver made contact with the signaller at the Thames Valley Signalling Centre to find out if the blanket emergency speed restrictions were in place on the diverted route. The signaller informed the driver that they were not aware of blanket emergency speed restrictions for the new route. It was later discovered that the notice had been filed by staff on an earlier shift and the signaller was not informed about it as the shift changed over. The provision of incorrect information by the signaller led to the driver travelling at normal line speed despite the fact that they had a copy of the late notice which detailed the blanket emergency speed restrictions for the new route. The information was in the driver’s bag and was not accessible whilst driving the train.
• At 20.50hrs, the 20.04 Bristol Parkway to Portsmouth Harbour service travelled at speeds of up to 71mph through 60mph blanket emergency speed restrictions which were in place between Bristol and Bath for Network Rail’s Western route. The driver was under the impression that the restrictions ended at 20.00hrs which was correct for the Wessex route however it was incorrect for the Western route which still saw the blanket emergency speed restrictions in place until 22.00hrs.

On the 19th of July 2022:

• At 11.50 hrs, the 08.05 Holyhead to Cardiff Central service was reported as passing over a hot axle box detector at 89mph, close to Craven Arms for Network Rail’s Wales route which had blanket emergency speed restrictions of 60mph in place.
• At 12.55hr, the 09.08 Milford Haven to Crewe service was also reported as passing over a hot axle box detector at 70mph at Tramm Inn near Hereford on Network Rail’s Wales route which had blanket emergency speed restrictions of 60mph in place. The driver had now seen the late notice and was not aware of the blanket emergency speed restrictions.

Some of the trains travelled substantially faster than the blanket emergency speed restrictions allowed with no reported consequences. It is also possible that further overspeeding instances did occur on the 18th and 19th of July but were not identified.

Further evidence also revealed that drivers called signallers in order to discover the situation with regard to blanket emergency speed restrictions over the two-day period of extreme heat as they were unsure of details, however, none of these led to overspeeding due to the drivers being provided with the correct information.

It was found that the overspeeding incidents took place due to drivers of the trains not clearly understanding where or when the blanket emergency speed restrictions were in place. One driver whose misunderstanding of the extent of the restrictions was added to further by a signaller who was also not fully aware of its correct application.

A RAIB report from August 2021 regarding trains overspeeding between Laurencekirk and Portlethen in Aberdeenshire found that blanket emergency speed restrictions did not always clearly convey information so that drivers could easily understand and remember when it needed to be applied. The report also found that drivers were not reminded of blanket emergency speed restrictions after booking on.

The format of the late notices may be part of the overspeeding incidents as the details describing areas, where blanket emergency speed restrictions were in place, were hard to memorise due to so many areas being listed on a single notice. Further investigation has also discovered that blanket emergency speed restrictions for neighbouring routes lead to drivers being confused as to whether they should follow the restrictions or not.

Network Rail has a procedure which allows route control centres to advise drivers of blanket emergency speed restrictions by using reminder broadcasts on the railway radio system which is configured to allow such broadcasts to be automatically played as a train nears the relevant signalling system. The system is only triggered to trains in the relevant geographic locations.

The instances of overspeeding saw none of the route control centres operating a railway radio system reminder broadcast. Despite the Western route being instructed to use the reminder broadcasts, they were not carried out due to signallers not being clear on which tracks they should implement the broadcast on. Other control centres opted not to use the broadcast system as the blanket emergency speed restrictions were only published the evening prior to coming into force and it was thought that drivers would already have seen the notices.

Following the Craven Arms and Tramm Inn incidents, Network Rail’s Wales route put the reminder broadcasts in place whilst the Western route utilised them on the days following.

A number of similar incidents which saw overspeeding at temporary, emergency and blanket emergency speed restrictions have also been investigated by the Rail Accident Investigation Branch. This latest safety digest has revealed the importance of:

• The structure of safety-critical documents – making sure that they are clear about what actions are to be taken, with formatting which supports ease of understanding and recall.
• The use of appropriate methods, such as available technology in order to ensure that important safety messages reach the relevant staff members so they are able to act.
• Rail staff to make certain they have fully read and understood safety-critical information which has been sent to them.
• The briefing of other staff who are taking over a position in order to ensure that adequate arrangements are in place and to support them recall this information where necessary.