Interviews

Whatever the weather

Weather is going to have an increasing effect on the railways so is going to play a bigger and bigger role in infrastructure and operations planning, due to changes in the climate and the UK’s meteorological conditions. RTM spoke to Met Office rail manager Steven Wallace to find out more.

The railways often find themselves a victim of the weather in this country, especially as it’s not just extreme storms and floods than can cause disruption – plain old British drizzle and leaf fall can cause low adhesion and traction/ braking problems, while overhead lines are often affected by ice in the winter and heat stress in summer.

The Met Office is hoping to offer more services to rail customers to help them with both immediate and longer-term planning for such weather. Steven Wallace, who manages such partnerships with railway businesses for the Met Office, spoke recently at the eighth UK Light Rail Conference in Manchester.

The Met Office and its partners already work with Network Rail, Scotrail, Translink Northern Ireland, Nexus in the North East and others, he said.

Changing climate, changing weather

Speaking to RTM after the event, Wallace told us: “Over the next 15, 20, 30 years, Network Rail’s parameters are going to have to change, because weather is going to change. Down south, you could see a shift over the next 30 years of as much as 10 degrees. So what does that means for the rail industry and what are you going to do to mitigate that risk?

“You might have done a lot of scoping surveys and planning based on the current climate, but as we move forward, that climate is going to change. It’s not a prediction, it’s actually happening. We can see the changes in weather that have occurred over the last 50 years and apply a model to that, looking at the low, medium and high carbon output scenarios and what the climate is going to look like over the long term. The rail industry plans 10, 15 and 20 years down the line, and we can assist as to what the weather’s going to look like in future years.”

He said the biggest threats included drizzle, because of the oxidisation effects on the tracks causing low adhesion, and leaf fall (one of the better-known problems, despite it being seen as something of a joke in the national press), which causes similar effects – extended braking distances, overruns, SPADs, loss of motoring performance and increased journey times. Wind, lightning and ice/heat stress on overhead lines are also common problems.

“It’s not just in the winter that we see extreme weather, we also see it in the summer,” Wallace said.

Specific services

He explained: “The technology we have in place for the rail industry can offer a high-definition, 360-degree view in real time, and forecasts over 24, 36 or 48 hours of what the weather’s going to be like, right down to 1.4-kilometre domains. We can tell them exactly what the weathers going to be within that domain.

“There is a public website, the National Severe Weather Warning Service (NSWWS), that we’re obligated to provide as a government body. That gives a very generic feel of the weather and a top-down overview.

“But when your parameters are more specific, say with leaf fall for the rail industry, that’s something we can tailor for you and offer a bespoke service for your routes and so on.

“We take a unique environmental dataset, couple that with a weather forecasting dataset, put the two together and we can say that the leaves are going to fall off the trees at this date.”

It can also offer data on the likely effects of more complex weather phenomena, such as the ‘weather blocking’ that was a major cause of March’s freezing weather.

“We’ve seen blocks of weather ‘stuck’, so this year we didn’t get January and February’s weather until March, because the winds and jet stream weren’t picking it up and pushing it across. We’ve seen a lot of weather coming in from the east rather than the west.

“We can make these forecasts and tell the rail industry, ‘it’s going to be quite a warm December, but March is going to be particularly cold’. So maybe without that knowledge they would have scaled back resources and so on coming out the tail end of winter, but in fact we can tell them to prepare for unusual weather in March and April, what you would have thought would be coming January and February.”

Preparing for major events

“Then there are the big weather anomalies,” Wallace said, “like the wind we got in Scotland in 2011, or the snow and ice we saw in Scotland a few years ago affecting the main route between Glasgow and Edinburgh, which was shut off for a couple of days.

“We can predict when these incidents will probably occur – these ‘one in a hundred year’ events.

“We can put extreme weather into context, and the climatology and what we’ve seen over the past decade suggests that looking forward, we can expect weather events of that size to happen about one in every ten years.”

Rail-specific information

Most weather-related issues are common to both light and heavy rail, Wallace said, from wind to lightning strikes. So light rail operators and transport bodies are also keen to make use of the Met Office’s services, Wallace suggested.

The ‘OpenRail’ web client, for example, was developed with the Met Office’s customers to show rail-specific information via an interactive map showing rail stations and rail lines, weather layers of interest, infrared satellite data, and rainfall radar imaging.

Weather elements can be colour-coded for clarity, and text warnings are also available.

The services tend to be completely bespoke to each operator or rail business, Wallace said, with different organisations having different priorities in terms of the data they’re most interested in. “That’s simply because of the geography and the topography in Scotland, Ireland, Wales and different parts of England,” he explained.

“It is so varied. On a basic level, the south west of England has more problems with flooding while the far north of Scotland will suffer more from extreme temperatures. It’s all unique, bespoke data – every service is tailored, and people in different parts of the county want to know different things.”