The Sleeper's Blog

29.06.18

Surviving the heatwave: are we truly the laughing stock of the world?

It’s safe to say the internet has not been kind to the rail industry for the widespread disruptions that took place this week as a result of soaring temperatures up and down the country. Passengers have taken to Twitter to call the UK rail network the “laughing stock of the world” because they’ve never heard of extreme temperatures impacting tracks in naturally hot countries.

So why have our tracks been baking under sizzling pressure, and why exactly is the UK the only one to experience this?

In a handy blog from Network Rail – perhaps partly released to deal with the cynics and engineer aspirants on the internet – the infrastructure owner explained that when we enjoy a rare summer heatwave, direct sunshine can cause rails to be as much as 20°C hotter than air temperature. Most of the network is designed to continue operating even when track temperatures reach a scorching 46°C – equivalent to an air temperature of around 30°C. But lately, they’ve been recorded at temperatures as high as 51°C.

Because they’re made from steel, they expand as they get hotter and begin to curve – or what is known as buckling.

So how does all this cause network-wide disruption? When remote monitoring systems alert engineers to the fact that a section of the track might be expanding too much and could cause problems for drivers, Network Rail introduces speed restrictions. Slower trains exert lower forces, create less heat and therefore reduce the chance of buckling.

But sometimes this isn’t enough, and rail can buckle even with speed preventions in place. This forces engineers to close down the line to repair the rails before trains can be allowed back on, which naturally can disrupt journeys as Network Rail waits for temperatures to drop down to acceptable levels before maintenance can be carried out.

And why is the UK the only country seemingly affected by this, as many have pointed out online? Well, the debate is a bit more complex than that. Naturally hotter countries will have rails stressed to cope with a much wider range of temperatures, or at least higher ones, whereas this week’s scorching climate is abnormal in Britain. The UK rail tension is set so that pre-stressed tracks only start to expand once the outside temperature hits 27°C, which is already a positive departure from the previous coping method, which involved leaving expansion joints along the line to allow rails to slide past each other as they expand (at the expense of a quiet and smooth journey).

Other countries, such as Japan and Austria, also use slab track, which means rails are laid on reinforced concrete slabs that hold them into place more rigidly (it’s the same material used in the Crossrail network). But it’s also more expensive to install than sleepers and ballast, meaning it’s hard to make a sound business case for widespread uptake.

But not all is lost without slab. To prevent tracks from getting too hot, Network Rail works closely with weather forecasters to take action ahead of time. Teams check track stability each winter in order to strengthen it before summer comes along, and they paint certain parts of the rail white so that they absorb less heat (they can be 5-10°C cooler than a section left unpainted).

Longer pieces of tracks welded together also mean there is much less chance of buckling in very hot weather because of reduced compression.

While this summer’s heatwave shows no signs of cooling off anytime soon, commuters outside of the capital can at least be thankful they don’t need to rely on the Underground – at least you won’t be exposed to the almost illegally hot temperatures of stations as a result of the London Clay.

Enjoying RTM? Subscribe here to receive our weekly news updates or click here to receive a copy of the magazine!

Image credit: Gareth Fuller, PA Wire

Comments

There are no comments. Why not be the first?

Add your comment

 

rail technology magazine tv

more videos >

latest rail news

TfL and TfWM join forces in knowledge sharing deal

20/07/2018TfL and TfWM join forces in knowledge sharing deal

A landmark collaboration between two of the UK’s biggest regions has been signed to pave the way to improve rail transport between the area... more >
DfT pledges ‘tough action’ on GTR, contract breach review due this month

19/07/2018DfT pledges ‘tough action’ on GTR, contract breach review due this month

GTR could be at risk of losing control of its franchise as early as this month depending on the outcome of a “hard review” into wheth... more >
Higgins urges Grayling to make decision on Yorkshire HS2 parkway station

19/07/2018Higgins urges Grayling to make decision on Yorkshire HS2 parkway station

HS2 Ltd’s outgoing chairman, Sir David Higgins, has urged the government to make a decision on proposals to create a parkway station on the... more >

editor's comment

23/01/2018Out with the old...

Despite a few disappointing policy announcements, especially for the electrification aficionados amongst us, 2017 was, like Darren Caplan writes on page 20, a year generally marked by positive news for the rail industry. We polished off the iconic Ordsall Chord (p32), hit some solid milestones on Thameslink (p40), progressed on ambitious rolling stock orders (p16), and finally started moving forward on HS2 (p14) ‒ paving the way for a New Ye... read more >

last word

Encouraging youngsters to be safe on the railway

Encouraging youngsters to be safe on the railway

This summer, Arriva Group's CrossCountry and the Scout Association joined to launch a new partnership to promote rail safety among young people. Chris Leech MBE, business community manager at the TOC, gives RTM an update on the innovative scheme. Recognising that young people are more likely to take a risk trespassing on railway tracks, CrossCountry and the Scouts have come together to encourage Britain’s younger generations to be... more > more last word articles >
board2

'the sleepers' daily blog

HS2: collaborate to innovate

17/07/2018HS2: collaborate to innovate

Dr Chris Goodier and Dr Steve Yeomans, of Loughborough University’s Centre for Innovative and Collaborative Construction Engineering (CICE), talk about four new HS2 research projects which are set to challenge how we design, build and monitor high-speed rail projects. No one doubts that HS2 must provide a platform for innovation, bu... more >
read more blog posts from 'the sleeper' >

comment

Elizabeth Line: a greener approach

17/07/2018Elizabeth Line: a greener approach

Howard Smith, operations director for TfL Rail and the Elizabeth Line, outlines the key features of the brand-new, eco-friendly Old Oak Common de... more >
iRail: investing in the future

17/07/2018iRail: investing in the future

The rail industry today faces many challenges, one of those being the skills gap in high- speed rail. However, events like iRail are doing their ... more >
HS2: collaborate to innovate

17/07/2018HS2: collaborate to innovate

Dr Chris Goodier and Dr Steve Yeomans, of Loughborough University’s Centre for Innovative and Collaborative Construction Engineering (CICE)... more >
Hydrogen trains: bringing the success story to the UK

17/07/2018Hydrogen trains: bringing the success story to the UK

Hydrogen-powered trains are already a reality in other rail networks in Europe. Now, working alongside Eversholt Rail, Alstom UK plans to bring t... more >

rail industry focus

View all News

interviews

Transforming travel in the north west

06/02/2018Transforming travel in the north west

RTM’s Josh Mines talks to Robin Davis, head of new trains at TransPennine Express (TPE), about the huge rolling stock change journey the co... more >
Thameslink: Nearing the end of the line

23/01/2018Thameslink: Nearing the end of the line

RTM’s Josh Mines catches up with Mark Somers, project director for Thameslink, on how the final stages of the programme are progressing and... more >
Modernising journeys in north east England

09/11/2017Modernising journeys in north east England

First Hull Trains is about to embark on the biggest fleet overhaul it has delivered since being set up in 2000. Managing director Will Dunnett te... more >