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State-of-the-art freight locomotives consume 18% less fuel than those now being used on Great Britain’s rail network, according to research by Ricardo.
The findings come after tests compared the fuel economy of GE Transportation’s latest Class 70 locomotive with that of the Class 66 locomotive, which is used for almost 90% of rail freight movements in Great Britain.
The research brings potential for dramatic emissions reduction in the rail freight sector, which is often cited as a cleaner alternative than road haulage.
The Class 70 is fitted with the latest technology, including commonrail fuel injection, a four-stroke engine and Miller timing.
Jim Buchanan, head of rail vehicle technology at Ricardo, said: “There is a new generation of vehicles that are using the latest technology for engines and bringing in auto stop/start systems that were pioneered on cars.
“The cost of fuel is the dominant cost in freight train operation. For anybody who is thinking of buying a locomotive or leasing one, then an 18% fuel saving is huge.”
He added that the tests provided an “extremely rare opportunity” to directly compare fuel consumption on railway locomotives. “To my knowledge, it’s unique to be able to do back-to-back testing like this – it just doesn’t happen,” he said.
GE commissioned tests to compare the fuel consumption of its latest Class 70 locomotive and the Class 66. The research took place at Wabtec Brush Traction’s facility in Loughborough. A rail freight operator loaned a mid-life Class 66 vehicle for the project.
Researchers fuelled the two locomotives from a tank that incorporated a weighing load cell, and the onboard compressor systems of both vehicles were deactivated to prevent spikes in power demand. The researchers measured the main and auxiliary electrical power generated, and for the Class 66 they took account of the mechanically driven auxiliaries.
During the tests, the locomotives ran at each power notch and the amount of fuel burned and power generated was measured, with allowances made for alternator efficiency and fuel energy content. The researchers then calculated the amount of fuel required to generate each kilowatt of haulage power. Using data on a typical duty cycle from rail freight operators, they also calculated the fuel consumption for each vehicle.
They found further significant fuel savings could be made on the Class 70 when closing down the engine during idling using the automatic stop/start system and auxiliary power unit, and a system that diverts power generated by dynamic braking to feed auxiliary loads. But Buchanan could not put a figure on this extra saving, as it depends on how often the vehicle is stationary.
The study builds on previous research by Ricardo that was commissioned by the Department for Transport and looked at how new technology could help reduce fuel consumption across the rail network. As specific fuel consumption data for the Class 66 vehicle was not available at that time, the researchers used estimates. These latest tests have revealed the vehicle used more fuel than estimated.
Buchanan said: “The fact that the measured fuel consumption of the older Class 66 was higher than the estimates of our report for the DfT makes the case for the retrofitting of new technology packages – in the absence of vehicle replacement – all the more compelling.”
Gary Lacy, PowerHaul platform leader at GE, said: “We wanted to demonstrate to our customers and other rail freight stakeholders the scale of fuel savings possible with this product.”