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

Government gives ‘hugely important’ £208m Belfast Transport Hub the green light

22/03/2019Government gives ‘hugely important’ £208m Belfast Transport Hub the green light

A new £208m Belfast Transport Hub with major rail and bus connections has been granted planning permission by the Department of Infrastruct... more >
New to-the-minute measures for train punctuality introduced to tackle delays

22/03/2019New to-the-minute measures for train punctuality introduced to tackle delays

New measures of train punctuality are to be released by train operators and Network Rail next month in a bid to improve performance. The Rai... more >
FirstGroup finalises £100m order for Hitachi trains as plans for London-Edinburgh rail link move forward

22/03/2019FirstGroup finalises £100m order for Hitachi trains as plans for London-Edinburgh rail link move forward

FirstGroup has finalised a £100m order for Hitachi AT300 electric trainsets in a partnership between the two companies to create a new Lond... 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

The West Midlands 30-year strategy

19/03/2019The West Midlands 30-year strategy

Malcolm Holmes, executive director of West Midlands Rail Executive (WMRE), outlines the West Midlands Rail Investment Strategy 2018-2047. The West Midlands Rail Executive was formed three years ago to give local authorities a direct influence over the award of the region’s main rail franchise. Working with the Department for Transpo... more >
read more blog posts from 'the sleeper' >

comment

26-30 Railcard: taking advantage of opportunities

19/03/201926-30 Railcard: taking advantage of opportunities

After a nine-month national trial, the rail industry launched its seventh National Railcard for 26-30-year-olds on 2 January 2019. Rail Delivery ... more >
Caledonian Sleeper: a railway icon re-imagined

19/03/2019Caledonian Sleeper: a railway icon re-imagined

The world-renowned Caledonian Sleeper, due to begin operations at the end of spring 2019, completed its first Scotland to London journey earlier ... more >
East West Rail: the next steps

19/03/2019East West Rail: the next steps

In January, five route options for the central section of East West Rail were published as part of a public consultation on the next phase of the... more >
Rail's role in transit-orientated developments

19/03/2019Rail's role in transit-orientated developments

Jonathan Bray, director at the Urban Transport Group (UTG), argues that transit-oriented developments are the future – and that rail has a ... more >

rail industry focus

View all News

interviews

Women in rail - is the industry on the right track?

12/03/2019Women in rail - is the industry on the right track?

RTM sits down with Samantha Smith, sole female member of the TransPennine Route Upgrade Alliance Leadership Team, to find out more about encourag... more >
TfN Strategic Transport Plan: not just for transport's sake

22/01/2019TfN Strategic Transport Plan: not just for transport's sake

Peter Molyneux, Transport for the North’s (TfN’s) strategic roads director, has been leading on the development of the seven economic... more >
Exclusive: Midlands Connect and WMRE talk collaboration and investment in the Midlands' railway

22/01/2019Exclusive: Midlands Connect and WMRE talk collaboration and investment in the Midlands' railway

In the jigsaw puzzle of regional transport decision-making, there must be collaboration and compromise. Midlands Connect media lead James Bovill ... more >