The European Committee for Standardization and a working group of the European Lubricating Grease Institute have each been working independently on specifications for greases applied to the sides of rails. Both groups set out to write a standard for greases that would reduce both wear and the levels of noise created by trains. The grease association, however, has criticized the specification adopted by CEN – the European Unions designated standards developer. In fact, the working group has said it will ask an industry organization to recognize its specification instead of CENs.

Some of the parties involved expressed confidence that differences can be resolved and a specification crafted that satisfies everyone. Still, the incident illustrates what can happen when multiple groups work on something as complex as a lubricant standard.

Train operators use two types of materials to control friction between rails and the wheels of railcars. Grease is applied to the side of rails to reduce as much as possible the friction between the rail and wheel flanges. The grease is dispensed by applicators mounted on rail cars, and operators try to program them so that it is only applied where wheels rub against the inside of the rail.

Different materials – friction modifiers – are applied to the tops of rails. Here operators are seeking some reduction in friction in order, for example, to improve fuel economy. But they cannot reduce top-of-rail friction too much without compromising a trains ability to break or gain traction when accelerating or climbing hills. Hence the use of friction modifiers.

Rail lubricant specifications have existed for some time, but the industry is working now to unify them across Europe – and in some cases beyond – while at the same time strengthening some performance parameters.

The main issue for us is to achieve interoperability, said Thierry Legrand, CEN program manager for industry, technology and infrastructure standards. In an interview with LubesnGreases he noted that train operators have traditionally been national organizations. But our networks have become increasingly integrated, and we want trains to be able to move seamlessly from one country to the next without concerns that there could be disruptions.

At the moment, we basically have achieved this for high-speed lines and what we call the trans-European networks. In order to achieve it for other trains as well, we need to have a series of minimum specifications – dimensions of the rails, dimensions of the wheels, performance.

Legrand added, So CEN is working within its original European context. But we are also linked to ISO, and this gives our specifications a normative global dimension.

CEN has been working on a series of three lubricant standards deemed important in achieving train interoperability between countries. The first would more accurately be described as a lubrication standard, as it addressed the application of greases to lubricate flanges on rail-car wheels. EN 15427 was adopted in 2008.

In June of 2012 CEN adopted the second specification, EN 16028, which attempts to set minimum requirements for greases lubricating between wheel flanges and rail sides. CEN indicated that part of the goal of this spec was to define greases that would help reduce train noise and wear at rail-wheel interfaces.

There are a lot of areas in Europe where trains are traveling very close to houses, Legrand said, and therefore there are always perceptions of disturbance for people living around tracks. In some cases, tracks have been moved, but we cannot do this in every situation. So there is a lot of effort being focused on trying to reduce the squealing caused by wheels rubbing against rails.

Train operators want to reduce wear in order to reduce the frequency at which they must perform maintenance on rails and wheels and ultimately replace them. Wear at wheel-rail interfaces flattens the curve of rail and flange. Operators periodically grind the surfaces to restore their shape, but eventually they must be replaced to avoid having railcars fall between tracks.

The CEN technical committee that wrote 16028 may have been trying to raise grease performance requirements, but ELGIs Rail Lubrication Working Group was not impressed. The latter group finished drafting its specification earlier this year and as this issue went to press was conducting round robin tests to verify that its tests are discriminating and repeatable.

During a meeting at ELGIs annual congress in April in Amsterdam, working group members said they were surprised to learn that CEN had been working on a similar standard. Moreover, they were critical of EN 16028, saying it did not accomplish its stated goal.

Many of the test methods required are not industry standards and [they lack] precision, said working group Chairman Henri Braun, of Exxon-Mobil Lubricants and Specialties. Specifically the group cited eight test methods for lacking test precision – methods covering parameters such as ability to resist water wash-off, miscibility with other greases, adhesiveness at elevated temperatures and resistance to movement at low temperatures.

The main performance aspects of friction and wear are not covered, Braun said. Working group members also complained that the EN 16028 includes several tests that are required for reporting purposes only – meaning that they are not part of the requirements for passing the spec. They add to development costs without adding any value, Braun said.

In view of its dissatisfaction with EN 16028, the ELGI working group voted to continue working on its specification. In addition, members also decided to raise their concerns with the Paris-based International Union of Railways (UIC) and to ask the operators association to recognize ELGIs spec instead of CENs.

He explained that CEN followed its normal procedures in adopting EN 16028, including a public enquiry at the workshop level and a period inviting public comment in each member nation of the European Union plus Macedonia, Turkey, Norway, Iceland and Switzerland. He also contended that the 15-member technical committee that wrote the spec included healthy representation from lubricant companies, rail operators, test laboratories and manufacturers of rolling stock and application equipment.

We had a reasonable range of participants from different parts of industry, Legrand said. We did not feel there were challenges we could not address, and we thought it was a good specification.

Legrand said he was not aware of any communication yet from ELGI but that CEN would still welcome the institutes input.

Obviously we are interested to have communications with any organization that can help us to improve our standard, he said. We would welcome an exchange.

The groups may have an opportunity to cooperate on another specification. CEN plans in the coming months to take up its third specification in the railway lubrication series – this one addressing top-of-rail friction management. UIC has decided to address the same subject, and one of its representatives says that all three groups will work together.

I work together with ELGI, CEN, Unife (the European Rail Industry) and ERA (the European Rail Agency) to synchronize the demands of lubricant companies, operators and manufacturers of track-side and on-board lubrication apparati, said Rolf Dollevoet, chairman of UICs project group for wheel-rail friction management. Dollevoet is employed both by ProRail, a government task organization charged with maintenance of the Netherlands national rail network, and by Delft University of Technology, where he is a professor for Railway Engineering. Everybody is willing to cooperate, he said, adding that UIC hopes to see the friction management specification completed in two years.