Thu. Jan 20th, 2022


The sound of trains departing from London’s St Pancras station on the 70-mile journey to Corby, in Northamptonshire, has changed.

After 2009, when the route was reopened for regular services, passengers heard a sharp crescendo of tours of the train’s underfloor diesel engines. Since May, however, they have heard the gradually-increasing whining of much quieter electric cars.

This change is one of several tangible signs on the journey of how the line has been transformed. Overhead wires now supply 25,000 volts of electricity to trains running as far as Corby; previously, the wires stopped 26 miles further south, at Bedford, meaning diesel trains were needed to travel the full distance.

The new electric trains are also accelerating faster than diesel-powered alternatives and their improved travel times are expected, based on previous experience, to shift more traffic to and from the roads.

The Bedford-to-Corby electrification is part of a multi-billion-pound effort to improve the overall efficiency and carbon footprint of the UK’s rail system by switching many more trains from polluting diesel to cleaner electric power.

Network Rail, the UK’s rail infrastructure owner, says electric train rides generate 20 to 35 percent less carbon per mile than those powered by diesel.

The program is being expanded by the UK: services on the busy Edinburgh-to-Glasgow route in Scotland switched to electric power in 2019 and the route between London and Cardiff became electric last year.

Similar efforts are under way in many other countries. Germany, which has already electrified much of its national grid, continues to electrify light-using lines. India has been electrifying thousands of kilometers of its routes every year lately,

38%

Part of the British rail network powered by electricity

Steven Hart, chief strategic planner for the UK’s Network Rail, says the aim is to get as many emissions out of the rail system as possible. About 747 km of British routes were electrified in the six financial years to 2018-19, but the UK still has only 38 per cent of its electricity network powered by electricity.

According to Hart: “[There’s also] that longer-term piece left to get rid of all diesel trains. You also have what is often called the ‘spark effect’. “People find electric trains more attractive, so they have the car thrown away to move to trains.”

The program is assisted by the emergence of a range of new technologies. This includes the development of new trains that can be powered both by diesel engines and by overhead electrical wires. Such technology should ensure that trains run on diesel power much less frequently when overhead lines are available.

At present, Japan’s Hitachi produces more than 500 wagons for trains with such capacity both to Great Western Railway, which operates services from London to Cardiff, Bristol and the West of England, and to LNER, which operates services from London to Yorkshire, north-east England and Scotland.

A Great Western Railways Hitatchi Class 800 train runs on diesel power in Dawlish, English
A Great Western Railways Hitatchi Class 800 train runs on diesel power in Dawlish, English © camerafirm / Alamy

Mark Gaynor, head of railway planning at the Rail Delivery Group, which represents train operators, says “bi-mode” trains, which barely existed in the UK five years ago, now make up 7 per cent of the total passenger fleet. “We’re definitely seeing more units with that technology,” he says.

He expects interest in such technology to grow. Cost pressure and unforeseen complications has resulted in electrification in many places being slower than expected. But bi-mode technology offers at least a temporary solution: it avoids the need to electrify tunnels and other less accessible areas while still bringing the benefits of electrification to the wider route.

Gaynor also expects greater interest in “three-mode” trains equipped with batteries as well as diesel engines and roof-mounted current collectors for overhead power connection. Porterbrook, a railway rental company, is currently converting old pure electric passenger trains into three-mode passenger trains and express package delivery units.

“You use power where it’s available, run on battery power where it’s not, then you have that diesel, all-in-one capability too,” Gaynor explains.

Meanwhile, the more efficient pure electrical technology continues to improve. Electric train cars have traditionally relied on DC electricity, but technological advances in recent decades have allowed them to be replaced with AC-powered equipment.

A Great Western Railways Hitatchi Class 800 train runs on diesel power in Dawlish, English
Roof-mounted current collectors collect electricity to power trains © MMXeon / Shutterstock

The new cars are significantly lighter and consume between 10 and 30 percent less energy than the old versions. In addition, they have allowed the introduction of “regenerative braking” on lines electrified with third rails – including some of the UK’s busiest commuter routes. A train that uses regenerative brakes generates electricity in its cars when it slows down and feeds them back into the network for another train to use while accelerating.

“That move to AC motors clearly provides an efficiency improvement,” says Gaynor.

Yet, for the most remote routes, it may never make sense to wire electrical wires. Electrification’s economy is much weaker where the high capital costs of the work are spread over a small number of services. Such questions are becoming increasingly acute in countries such as the US, where the vast rail network is scarce electrified and where most traffic is heavy, energy intensive load.

Nevertheless, Hart insists that technology be developed to ensure that any area can be served by trains that make no carbon emissions. Porterbrook is experimenting with a train he calls Hydroflex, which uses carbon-free hydrogen fuel cells to power its electric motors. France’s Alstom has sold a similar hydrogen-powered passenger train – which it iLint – to a number of European countries. And the American group Caterpillar has launched a hydrogen-powered heavy-duty locomotive that has been put into operation alongside Canada’s Canadian Pacific.

Dizzying progress is possible, Hart says, because of the billions of dollars invested in the greening of motor vehicles – the mode of transportation from which programs such as Corby Electrification hope to steal traffic.

“We are making a lot of progress that has been made in the automotive sector and we are translating it directly into a rail environment,” Hart says. “We are almost able to drive the dresses of the research and development that is taking place in the automotive sector.”



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