More than half of the maintenance costs for tracks and freight wagons are due to wear. Cracks in wheels and rails account for most of that wear. Together with organizations who are connected to railway traffic, Chalmers Railway Mechanics
(Charmec*) has developed criteria for assessing the risk of cracking in wheels and rail. Anders Ekberg is an assistant professor at the Department of Mechanics and Maritime Sciences and director of Charmec:
“More and more railway traffic goes on the same network, which leads to smaller windows for maintenance. But by being able to predict cracking, the risk of operational disturbances, unplanned maintenance and environmental impact is reduced. Then the costs can also be kept down. And that is a necessity for a functioning and efficient railway”, he says.
The basis for the criteria lies in research done by Charmec. There, research on cracking in the contact between wheels and rails has been linked to research in railway dynamics. Results are the criteria that today are the standard tool for engineers who design wheels and boggies for trains. In addition, they are implemented in most commercial programs used to analyze how trains load the track.
Catches risks at the design stage
The criteria developed at Chalmers are also an important ingredient in design, virtual testing and product approval. This means that engineers, already at the design stage, can ensure that the design of rails, gears, wheels and boggies has properties that give an acceptable low risk of cracking.
“I see the development of these criteria as an important part of what I consider to be the core of the railway's digitization: Having such accurate numerical simulations that only validation is needed in fields when new products are introduced or extensive maintenance is carried out”, says Anders Ekberg.
Examples, where the criteria saved a lot of money, are the design of new gear geometries that reduced the maintenance costs for the gears by in the order of 20 per cent. They have also been used to optimize wheel profiles on the ore rail, which is a contributing reason why the traffic is now starting to be upgraded from 30 to 32.5 tons of axle load.
*Charmec is a national centre in railway mechanics. Read more about Charmec
Text: Anders Ryttarson Törneholm