Engineering, Products & Technology

Getting smart about bearings

Combining the latest technology with a century of expertise, SKF is ensuring that bearings are providing ever more uptime for railway operators.

Combining the latest technology with a century of expertise, SKF is ensuring that bearings are providing ever more uptime for railway operators.

The modern railway network is perhaps the most complex system that the general public interacts with on a daily basis. Highly interdependent, geographically dispersed, and with a mix of analogue and digital technologies, getting to work on time depends on thousands of subsystems working in concert.

From the latest digital communication systems to decades-old ballasted track, every system is vital, however the closer one gets to the point of interaction between static and moving elements, the more critical parts and components are. At the centre of this nexus are the bearings that connect a train’s wheels and axle to the bogie and car.

As Patrick Hofstadler from bearing manufacturer SKF explains, bearings have a critical role to play in ensuring that trains are reliable and available.

“The failure of a bearing is directly related to trains not being on time, trains having to be taken out of service, and maintenance intervals being interrupted.”

During scheduled preventative maintenance periods, bearings are one of the critical components that must be checked to ensure they are in good condition. With new technology that can track the health of a bearing and intelligent approaches to maintenance and upkeep, the time a train is in the workshop can be shortened and the lifetime of components extended, ensuring higher levels of availability and lower costs.

“The maintenance cycle is what causes the trains to be out of service. It’s what causes cost as well as time to maintain the passenger schedules,” said Hofstadler.

“Condition monitoring helps these maintenance cycles to not be any longer than they need to be, because there has already been a lot of data collected. Rather than having to check every single bearing, maintainers can address those bearings that have come up as needing attention, shortening maintenance cycles, which means the train will go back into service without delay.”

Condition monitoring for critical components

SKF has developed two technology platforms, Insight Rail and IMx Rail, that monitor indicators such as vibration and temperature to give operators insights into the health of their bearings. This data is used to improve availability.

“The most important thing by monitoring the bearing’s health, is that you’re able to predict certain maintenance intervals,” said Hofstadler.

With these solutions deployed in the field, SKF is already on track to help increase the total life of bearings in major passenger rail networks from 1.2 million service kilometres to 1.6m kilometres, a 33 percent improvement.

These modern technologies address some of the most fundamental issues faced by bearings which have been part of the railways for decades. For example, there are six primary factors which cause a bearing to fail: fatigue, wear, corrosion, electrical erosion, plastic deformation, and fracture and cracking.

These factors can be addressed by a standard maintenance practice, greasing. However, with more intelligent information about the amount of grease required, time between maintenance cycles can be extended and time spent in the workshop can be reduced.

Under its Smarter Rail Services banner, SKF is enabling operators to access its knowledge in the maintenance and upkeep of bearings. When it comes to greasing, SKF can ensure that the right amount of grease is applied in the right way, and inventory control is left to the experts.

“When it comes to greasing there’s always a specific amount of grease that is measured and weighed as the grease is injected into the bearing,” said Hofstadler. “Too much or too less grease can cause the bearing to overheat.”

This in-house upkeep enables operators to spend more time doing what they do best – running rail services.

These services extend to other areas of the bearing lifecycle as well.

“SKF offers refurbishment services, so in any situation where the operators and maintainers have failed bearings or bearings that are showing signs of possible premature failure, we can refurbish those bearings, as well as provide inspection reports to the customer so they understand in more depth what may have happened,” said Hofstadler.

Not only does remanufacturing and refurbishing of bearings reduce costs and cut down on wastage, SKF is able to provide these services locally, through its services centres in Perth and Williamstown, Victoria. After detecting when a bearing is reaching the end of its useful life through condition monitoring, sending bearings for refurbishment by the OEM, in this case SKF, allows for operators to limit capital tied up in spare part inventories.

“Previous practices were that operators and maintainers would have a very high stock level on spare parts, just in case of bearing failure, this predictive maintenance through condition monitoring allows you to reduce your stock levels,” said Hofstadler.

Today, SKF is offering rail organisations its 100/100 business model, where if 100 bearings are sent for refurbishment, 100 refurbished or new bearings will be returned to the operator, no matter the scrap rates. Not only does this model take the variability out of the hands of the operator, but by monitoring wear rates SKF can provide intelligence back to the operator to extend the lifecycle of their bearings.

“All the information from every single bearing and refurbishment is saved in a database system so we can track each bearing based on its serial number. We know the history of the bearing and therefore we can provide the customer with database reporting on bearing batches that we’ve refurbished for them, from the new batch to every single refurbishment.”

As Hofstadler describes, this kind of knowledge is a result of SKF’s heritage in its field.

“As a manufacturer, SKF has been in business for over 110 years now so there’s a lot of experience, historical value, and global information sharing through different applications.”

Having this knowledge and expertise in each bearing’s upkeep, repair and refurbishment means that this critical link is more assured than ever.

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