Separator creates cost and environmental savings for rail freight giant DB Schenker

Alfa Laval separators have been used at sea for cleaning impurities from bunker fuel oil and keeping lube oil free of water for almost a century. Derek Clark’s idea was to use the same technology for the same purpose on railway locomotives.

The ground-breaking idea worked perfectly and the investment paid off in just a few months. Dirty oil that was previously considered waste is now reused, and besides saving money, the solution also reduces environmental impact. The idea earned Clark a prestigious Railfreight Engineer of the Future Award for “delivering pioneering locomotive fuel-saving initiatives”.

Reuse, don't replace

When he started at his new job at the main maintenance depot of logistics giant DB Schenker Rail UK in Nottingham after 16 years at sea, Clark observed a different approach to oil in the two industries. “I couldn’t help but notice how much was thrown away here,” he says.

Driven by DB Schenker Rail UK’s environmental concerns and drive to reduce costs, Clark realised there must be potential to use separators to clean locomotives’ oil. His initial idea was to get more life out of lube oil when locomotives came in for service by cleaning it and reusing it, rather than replacing it with new oil.

Working in his own time, Clark investigated the issue and put the case to his superiors. DB Schenker Rail UK soon invested in two Alfa Laval separators, which Clark modified slightly. And then he found a second use for them. “I found out that we had a lot of dirty diesel that we either stored or just burned off. I thought ‘why are we burning it when we could use it again?’ I knew that separators could be used for cleaning diesel as well, so that’s what we started doing,” he says.

Profit from waste

There were a large number of locomotives in long-term storage on site, and the fuel in their tanks had become damp due to condensation, which in some cases this had led to microbial contamination. So these locomotives were drained into a spare storage tank and an Alfa Laval Oil Cleaning Module (OCM) was put to work for a week.

So much oil was saved for reuse that DB Schenker Rail UK’s initial investment was paid back within about four months. “Plus we turned a profit,” says Clark. “We still get some locomotives coming in with microbial contamination which have to be drained, so the savings are ongoing.”

Besides the money savings, there are environmental benefits of using separators to clean oil. “We don’t have lorries coming in and out to into empty the tanks,” says Derek. “Plus we don’t burn waste oil anymore.”

Cleaning the lube oil of contaminants that abrade metal surfaces and increase friction can also increase engine life. “Some of the engines we have get very dirty very quickly – it is mainly carbon that builds up,” says Derek. “The last time I cleaned one I got half a kilogram of solid material over two days.”

More potential

The idea has generated considerable interest in the UK rail industry, and Clark is now investigating other applications for Alfa Laval separators on locomotives. One involves using a smaller Eliminator Filter fitted permanently to the engines to filter, automatically backflush and centrifuge the oil while the loco is in operation, not just when it comes in for service.

So while used oil was once treated as waste and either burned or otherwise disposed of, Clark’s idea means that less oil has to be bought, and then that oil goes further. Should it be taken up as a standard operating procedure in the rail industry, the savings would be considerable. “If the rail industry was cleaning engine oil like it’s done at sea, you could extend the life of the oil by about 50% with associated cost savings,” says Derek. “And then further up the line you get rid of dirty oil and the pollution that it generates. Using separators just makes good sense.”