Rail Industry Focus

Building trains for a partially electrified network

Jon Seddon, director of strategic programmes at Bombardier, discusses the environmental performance of rolling stock. Kate Ashley reports from Railtex 2013.

Improving the environmental performance of rolling stock can bring much wider benefits – including savings in energy, maintenance and operating costs.

That was the key message from Bombardier’s director of strategic programmes, Jon Seddon, speaking at Railtex 2013.

“This is a challenge that rail businesses are facing all around the world. This is not just a UK issue,” he said.

Energy efficiency is a major priority for train operators today, both from an environmental and cost perspective. Rail transportation is often highlighted as the most environmentally friendly mode of mass transport, producing significantly lower CO2 emissions than other modes of motorised transport such as cars or planes per passenger kilometre.

“We’re starting from a good place, but we need to keep pushing on.”

Seddon focused on how companies can improve the environmental performance of rolling stock through four key measures: reducing traction energy; switching to electric; reducing energy expended in non-traction uses; how rolling stock support services can help to reduce the number of non-passenger miles in passenger trains, and the waste that that implies.

Driving style

Adopting “fairly simple” design measures such as low mass bogies can result in 5-7% energy savings, he said, translating to huge cost savings in large fleets.

“Reducing mass is one of the most obvious ways to tackle excess traction energy, but helping drivers drive more effectively can also afford considerable gains.

Seddon added: “This is not about moving to composite technologies, this is stuff that’s been around for a number of years – what’s interesting, but what is less well understood, is the impact that driving style has on energy consumption.

“In our experience, this can be maybe three times the impact of mass reduction. “Where we might see a 60% energy reduction from mass reduction, it’s the additional 18% by giving good advice to drivers about target speeds and how they can modify their style, while still maintaining timetable performance.

“It’s indicative of the savings that are there without moving to high-risk new technologies.”

Driver advisory systems can help operators to “intelligently combine multiple goals” – punctuality, reduced maintenance requirements and energy savings, for example.

They recommend coasting opportunities to drivers, and help them to make speed and acceleration decisions that will optimise efficiency without sacrificing punctuality, or the number of services an operator can run.

Such integrated systems are becoming “much more deliverable”, and at a significantly lower cost. The business case for implementation is getting stronger and stronger all the time, Seddon said.

A partly electrified network

The Government has major electrification ambitions, of course – the Great Western Main Line, the Midland Main Line, the Welsh Valleys, the North West, Edinburgh-Glasgow – but even after this significant programme of works is complete, a substantial proportion of the network will remain unwired.

Seddon said: “We are going to have, for the foreseeable future, a network which continues to be partly electrified, albeit more so than today.

“This is not an uncommon problem; it’s a problem which exists pretty much everywhere apart from Switzerland, and [there are] countries with no electrification whatsoever. How do you deal with a network which is partly electrified, and on which we want to provide seamless journeys for passengers, that suit their needs?”

Electrifying the whole network would be incredibly expensive, and while a long-term vision, would also require a huge amount of planning in terms of civils and structures, future rolling stock, maintenance and so on.

Seddon noted that hybrid capability grants the benefits of electrification where the infrastructure is in place, and eliminates the need to invest in further infrastructure where there isn’t sufficient traffic fl ow to justify it. Seddon highlighted the roll-out of more bimode trains as a great opportunity to gain energy benefits in a cost-effective way.

Others in the industry have questioned the value and expense of bi-mode trains, such as the IEP fleet – for example, the weight of the diesel engine and the design compromises that must be made over a purely electric or purely diesel train.

Combining savings

Aerodynamic performance of rolling stock will be important for the introduction of high speed rail, and Seddon said improving environmental performance will have knock-on beneficial effects in a number of areas.

Small-capacity energy storage in a hybrid train can provide acceleration boosts, and when used with a driver advisory system, can see the energy saving per cycle twice the capcity of the energy store itself.

“The combination of the two factors gives a very worthwhile saving – these can make a real impact.”

Retraction and non-traction

Re-traction of existing units is also an option, with typical savings of 15% as well as “a number of important side benefits” in terms of system reliability and reduced traction maintenance requirements. An often overlooked risk is the obsolescence of materials and skills for supporting 1980s technology.

He explained: “That’s a challenge that we continue to address, but is avoided if we are able to make this kind of investment.”

Non-traction energy is “a smaller piece of the pie, but important”. New technology such as smart stabling can save energy overnight whilst still having trains ready with lights and heating for passengers and drivers in the morning through remote communications controls.

This cuts depot costs when trains are in remote locations and means energy is only being used when necessary. Smart stabling is the kind of small action, like turning off the lights when you leave a room, that can add up to a large saving when carried out routinely and on a big enough scale.

Seddon said: “We can now easily control and ensure that auxiliary loads are managed actively, unnecessary loads are removed. We’re seeing significant energy savings from careful focus from some of these smaller things.”

Reducing non-passenger miles

In terms of reducing non-passenger miles, better management of rolling stock can significantly impact environmental performance. This involves minimising the need to move trains to depots for repair, for servicing intervals and for refuelling and maximising the effectiveness of the depot intervention when it is needed.

“There’s a whole number of separate, targeted interventions that nibble away at this issue of unproductive mileage,” Seddon said. “One of the key enablers of that is condition-based maintenance.

“We are seeing benefits in modern fleets today across the whole of the UK in being able to understand the condition of assets and apply and execute maintenance accordingly.”

Combining a lightweight train fitted with drivers’ advisory systems, regenerative braking, designed for low maintenance with intelligent stabling, could bring “a very significant improvement for the next generation in the environmental performance of our rolling stock”, Seddon concluded.