Climate change: Would rail or road be more affected in the UK?

[squizzler]

On the radio this morning there is another article on potholes opening up in the highways network. Apparently the reported damage that motorists claim to be caused by potholes to date this year already exceeds all that from last year. There are a lot of variables of course - maybe there are more ambulance chasers encouraging spurious claims? Maybe motorists are simply being less careful in driving at an appropriate speed for conditions? A pothole is after all a passive thing on the ground that does not exactly jump up and attack cars any more than roadside trees are to blame for the damage caused to cars that come off the carriageway and hit them! And if the highway authorities were as good at filling the potholes as news agencies were at filling the lighter hearted segments of their output with stories on potholes the streets would be fixed in no time.

That said, we have just had in the UK a very variable winter with very wet periods interspersed with unusually cold snaps. This seems to be consistent with some models of climate change that predict hotter summers and colder winters as the various ocean and atmospheric currents shift about. These conditions self-evidently damage road surfaces. Compared to the older days when the seasons were more predictable, does this mean the highways effectively now experience several winters each year? Does climate change simply prevent highway authorities from providing the road surface quality we were used to?

Railway managers on the other hand are also concerned by resilience to climate change. Much of the network is older than corresponding motorway and trunk roads. The embankments are steeper and less stable and there are low points vulnerable to flood damage and other effects of climate change. Rails can bend in extreme heat. Both overhead and third rail electrification are recognised as potential points of weakness.

We do however see that European countries with severe snow in winter (Scandinavia, Switzerland, etc) have better public transport systems than we do. This may be viewed as a cultural thing, but of course the climate defines your national character. So are the railways inn a better position than highways to weather climate change. And would the severe weather expected from climate change shift UK economics to favour railways?

 

[Bantamzen]

For general day to day weather damage, I'd say roads would suffer more due to the vastly greater amount of miles of it compared to rail. However I'd expect any damage caused to rail to have a greater effect in terms of lengths of disruption, additional travel time caused by diversions or mode replacements, and per mile to be much more expensive.

 

[yoyothehobo]

This year we had a major problem with freeze thaw, prolonged very cold periods, snow melt, refreezing etc which has been the main driver in tearing up the roads.

It is unclear whether this would be the major long term pattern associated with climate change.

What I think is most likely is that we get much wetter winters and I think this will have a much greater effect on the railway than the roads. The majority of our road network has been built in the 20th century, whilst the railways were predominantly victorian era and the infrastructure to match. These take lots of money and time to rectify, think Eden Brows for a big example.

Embankments and cuttings are particularly susceptible to drainage issues, landslips, undercutting by streams, rivers etc. I think we will see much more along these lines of disruption than the snow and frost.

I dont think climate change will particularly change how we move about, there will be major shifts in terms of how vehicles are powered but the nature of how we live and expect to live means that we will still desire point to point journeys a lot of the time, congestion would likely be the thing to drive more people onto the rails.

 

[edwin_m]

Also the road network is dense enough that there is pretty much always some sort of alternative available if a particular road becomes unusable. This would be very disruptive for a major road, as anyone caught up in diversions when the M1 is blocked by a daytime accident will testify. However, while not all roads have been built in recent decades, most of the major roads have and are therefore less likely to be affected.

On the other hand, there are vulnerable sections of the rail network where there is no rail diversionary route, Dawlish being the most obvious example.

 

[Chris999999]

That said, we have just had in the UK a very variable winter with very wet periods interspersed with unusually cold snaps.

Seems like how winters always have been - periods of rain and times when temperatures dropped below zero. Nothing different there then.

 

[squizzler]

Also the road network is dense enough that there is pretty much always some sort of alternative available if a particular road becomes unusable. This would be very disruptive for a major road, as anyone caught up in diversions when the M1 is blocked by a daytime accident will testify. However, while not all roads have been built in recent decades, most of the major roads have and are therefore less likely to be affected.

On the other hand, there are vulnerable sections of the rail network where there is no rail diversionary route, Dawlish being the most obvious example.

You refer to how the railways might cope in the event of major weather disruption vis-a-vis road. However I think it is more nuanced. The railways seem to be more binary in how they get disrupted: i.e. they are either running or not. On the other hand you can still decide to ride, walk or drive on the roads no matter how bad conditions are but you journey quality will be degraded. The carriageway surface gets degraded by poor weather (cracked by snow and water, melted by hot sun) and remains degraded longer.

 

[furnessvale]

Taking the case of the Buxton line. Once upon a time the railway was relied upon to keep the town connected when the roads were blocked by snow.

Nowadays, the railway is the first thing to block and the last thing to reopen.

If that is repeated across the country then I would say rail will suffer worst.

 

[Mikey C]

I imagine council cuts are more a factor in why roads are in such a poor condition, as potholes are left longer, and when they are filled it's a quick fix which leaves a weakness around the edge of the repair.

The UK has a pretty moderate climate really, I'm sure other countries will be affected by climate change more than us, especially as most of the critical road and rail infrastructure is well away from the coast (Dawlish being a notabe exception)

 

[ChiefPlanner]

I imagine council cuts are more a factor in why roads are in such a poor condition, as potholes are left longer, and when they are filled it's a quick fix which leaves a weakness around the edge of the repair.

The UK has a pretty moderate climate really, I'm sure other countries will be affected by climate change more than us, especially as most of the critical road and rail infrastructure is well away from the coast (Dawlish being a notabe exception)

From a main line point of view - but the Cumbrian and Cambrian coast lines remain an issue - along with certain area like Cowley Bridge Junction and the Somerset levels.

Embankment and cutting stability - many well over 100+ years old remain a concern all round , everywhere......

 

[AM9]

From a main line point of view - but the Cumbrian and Cambrian coast lines remain an issue - along with certain area like Cowley Bridge Junction and the Somerset levels. ...

Areas like the Somerset levels would be unsustainable and return to their natural state, i.e. flood plains. Spending ever increasing amounts of climate-changing energy and materials would just accelerate the rising sea level, hastening the flooding until it became a lost battle. Similarly, efforts to prevent a rising sea eroding cliffs such as in south Devon would eventually (maybe sooner than many think) make keeping storms off them impractical.

 

[DanTrain]

Taking the case of the Buxton line. Once upon a time the railway was relied upon to keep the town connected when the roads were blocked by snow.

Nowadays, the railway is the first thing to block and the last thing to reopen.

If that is repeated across the country then I would say rail will suffer worst.

Interesting case that: the Hope Valley is the opposite, rail can often be the only way in and out at times, particularly Edale which is very cut off by road.

 

[Dr Hoo]

The Hope Valley Line has been blocked quite a few times recently by climatic events. Trees blown over last year and lots of icicles in the tunnels or snowdrifts at Chinley more recently.

Tiny Edale (population <400, otherwise accessible only by unclassified roads and no regular bus services apart from for schools traffic) has also suffered acutely from the appalling industrial relations climate on Northern, having no Northern trains whatsoever on guards' strike days recently.

It has probably had the worst rail service dependability for decades over the past year.

 

[squizzler]

Interesting case that: the Hope Valley is the opposite, rail can often be the only way in and out at times, particularly Edale which is very cut off by road.

The Heart of Wales line is often knocked out by bad weather, and in the recent winter frequently remained closed after alternative routes over highway were cleared.

But that is not really the point I was making. When driving from England to Wales the highway surface used to become very smooth when you crossed the border. Ironically, when taking the Heart of Wales line the ride quality would deteriorate as you went onto jointed track.

With climate change, winter snowfall seems to come very fast, and I understand this is what causes the damage. I recall hearing that when salt is thrown onto the snow the melting process draws heat off the carriageway and freezing the water within the tarmac, thereby breaking up the carriageway. More, and heavier dumps of snow will tend to make this worse. Maybe somebody knows more about the physics of this?

Now spring has come the Welsh highways are much less smooth than they used to be, more akin to what the English ones used to be. The English roads in the meantime have got worse! The railway ride quality feels just the same as before, so this means that as the highways take a battering over several snowy winters the highways lose their advantage (or, if you prefer, the railways increase their lead!).

 

[Altfish]

The increase in potholes is due to a reduction in maintenance budgets.
Good, well maintained roads do not deteriorate in frost.
Roads with cracks and small holes deteriorate, cracks become crevasses, small holes become large holes.
The answer to potholes is maintenance, but that needs increased budgets; when the budget is cut and we get a cold winter, it comes back to bite you and will cost more in the long run.

 

[Taunton]

Areas like the Somerset levels would be unsustainable and return to their natural state, i.e. flood plains.

I'll just point out that the Somerset Levels are better at flood alleviation than they used to be, and are actually getting drier - in steam loco days Langport Bridge used to flood every winter, and ducks come swimming between the platforms. Of course, then, the railway Carried On through it, in fact locos would actually have their fire in the grate extinguished by the water as they came slowly through, but would then arrive at Taunton on the reservoir of steam that remained in the boiler.

No chance of such competence nowadays.

 

[squizzler]

The increase in potholes is due to a reduction in maintenance budgets.
Good, well maintained roads do not deteriorate in frost.
Roads with cracks and small holes deteriorate, cracks become crevasses, small holes become large holes.
The answer to potholes is maintenance, but that needs increased budgets; when the budget is cut and we get a cold winter, it comes back to bite you and will cost more in the long run.

The problem with that is that damage to highway surfaces are predominantly caused by heavy wagons and they do not pay in proportion to the damage. Research done by Campaign for Better Transport (pdf) suggests that the damage of a lorry axle can be 150,000 times that caused by that of your car.

The problem with this iniquity is that people are not stupid and if motorists are asked to pay for highways that are wrecked by commercial vehicles, they might say "well if you can't beat them, join them" and use a heavy commercial vehicle for their personal journeys (the bus). Thereby reducing the pool of motorists who can be taxed for road upkeep and increasing the demand for heavy commercial vehicles which are causing the damage.

 

[furnessvale]

The problem with that is that damage to highway surfaces are predominantly caused by heavy wagons and they do not pay in proportion to the damage. Research done by Campaign for Better Transport (pdf) suggests that the damage of a lorry axle can be 150,000 times that caused by that of your car.

The problem with this iniquity is that people are not stupid and if motorists are asked to pay for highways that are wrecked by commercial vehicles, they might say "well if you can't beat them, join them" and use a heavy commercial vehicle for their personal journeys (the bus). Thereby reducing the pool of motorists who can be taxed for road upkeep and increasing the demand for heavy commercial vehicles which are causing the damage.

Before anyone jumps in and says that the CBT research is biased, the research was carried out many years ago in a U.S. university with no axe to grind. Basically damage to the road surface is proportionate to the fourth power of the axle load.

Secondly if motorists are directly asked to pay for damage caused by HGVs (as opposed to the current system of them paying through private vehicle taxation with no say in the matter), the natural reaction would probably be, "don't ask me to use a bus, take those damaging lorries off the roads and put the freight onto rail".

 

[Altfish]

The problem with that is that damage to highway surfaces are predominantly caused by heavy wagons and they do not pay in proportion to the damage. Research done by Campaign for Better Transport (pdf) suggests that the damage of a lorry axle can be 150,000 times that caused by that of your car.

Yes, but well built roads do not get potholes and wagons can only wear them out faster which if they are resurfaced at the correct interval will not get potholes.
Most damage is by utility companies digging the road and not reinstating correctly and damage due to MVAs and the like, which again are not competently repaired.

 

[squizzler]

Whilst there are some heat related speed restrictions in force, the carriageway surface is actually melting in many roads. The damage where chunks of tarmac have been pulled off the surface will probably be the start of some potholes in the winter, whereas the railway speed restrictions will go as soon as the weather becomes cooler. Again, to me it seems the rail mode bounces back faster after extreme weather.

 

[The Ham]

Before anyone jumps in and says that the CBT research is biased, the research was carried out many years ago in a U.S. university with no axe to grind. Basically damage to the road surface is proportionate to the fourth power of the axle load.

All that is well known, it is why when roads are designed they only take into account likely HGV movements within their design life.

The Design Manual for Roads and Bridges (DMRB) has a calculation for working out the number of axels of larger vehicles based on the design life of the road. This is then used to calculate the thickness of the road construction (excluding the sub base, which is based on the strength of the subsoil).

However, road surfaces are cheap to repair (if done well and on time) compared to the rest of the road structure should the lower levels be too thin, or worse the sub base get wet (either from ground water or from surface water, however the latter shouldn't happen on a well maintained road).

It's one of the reasons that those car drivers who shot shout about how cyclists should pay for the upkeep of the roads make themselves look stupid. As cycles cause next to no damage to roads. In fact they cause next to no damage to footways (which are often used as cycleways, and even custom built cycleways use first construction) which have a much thinner construction thicknesses (mostly even those are too thick, as they are designed for the occasional car parking on them).

 

[Lucan]

On the other hand you can still decide to ride, walk or drive on the roads no matter how bad conditions are

No you can't, because the police close the road.