What is Risk Based Maintenance? How Railways Are Getting Smarter About What They Maintain
- thepwayengineer
- 12 minutes ago
- 5 min read
As the pressure increases on railway infrastructure to perform reliably with fewer disruptions, railway maintainers are being asked to do more with less. Less access to the track, tighter budgets, and higher performance expectations. This challenging environment has made one approach more relevant than ever: Risk-Based Maintenance (RBM).
In this post, I’ll break down exactly what RBM is, how it compares to traditional strategies like reactive and preventive maintenance, and how it's transforming the way railway assets are managed. I’ll also take you through the benefits and limitations of risk-based maintenance, and how data and technology are helping it take hold across the industry.
What is Risk Based Maintenance?
Risk-based maintenance is a strategy that organisation can use, that prioritises maintenance activities based on two key factors:
The likelihood of an asset failing, and
The consequences if that asset were to fail
In simple terms: the riskier or more likely an asset is to course problems, the more attention it gets.
This approach helps ensure that the right work is done at the right time, improving safety and reliability while avoiding unnecessary maintenance activities.
What is an "Asset"?
According to ISO 55000 - Asset Management - Overview, Principles and Terminology , an asset is:
"An item, thing, or entity that has potential or actual value to an organisation."
When it comes to the railway, an asset can be any component that has a functional role and value to the operation of the railway.
Common railway assets include:
Track components (rails, sleepers, fastenings, ballast)
Signalling systems (track circuits, interlockings, detection systems)
Structures (bridges, tunnels, stations)
Electrical systems (overhead line equipment, substations)
Rolling stock (locomotives, wagons, carriages)
An Example of Risk Based Maintenance
Let’s say we’re looking at two sections of track
Track A is a high-speed line (100mph/160km/h) with 10 passenger trains and 2 freight trains per hour.
Track B is a low-speed line (20mph) with only 2 freight trains per week.
Track A clearly has higher usage and carries more passengers at higher speeds. This makes both the likelihood of failure and the impact of any failure significantly greater.
As a maintainer, it makes sense to inspect and maintain this section more frequently. This will prevent failures and reduce the risks And that’s essentially the core idea behind risk-based maintenance.
Other Maintenance Approaches & Why RBM is Different
There are two traditional maintenance approaches still used today:
Reactive Maintenance – This is maintenance that happens after something breaks. It’s often referred to as “fix-on-failure” and is best suited to non-critical assets where failure is inconvenient but not dangerous.
Preventive Maintenance – This involves servicing assets on a fixed schedule, regardless of actual use or condition. Think of it like servicing your car every year, even if it hasn’t left the driveway.
Risk-based maintenance takes a data led, more targeted approach by focusing maintenance resources where they’re most needed to keep railway running safely and efficiently, while also helping control costs.
How is the Likelihood & Consequence of Failure Calculated?
To apply risk-based maintenance properly, railway engineers must assess both likelihood and consequence of an asset failing.
Likelihood of Failure
This assessment is typically informed by data or characteristics about the asset.
When it comes to looking at the likelihood and asset will fail, the data looked at might include:
Patterns of historical failures
Actual usage levels (not just estimates)
Wear and degradation rates over time
For the consequence or risks associated with the asset failing, the focus is likely to be on factors such as:
Line speed
Frequency of trains
Train type (passenger vs. freight)
Location
Asset age and condition
History of faults or incidents
This assessment process may also consider aggravating or mitigating factors that are specific to each asset or location. Local maintainer and operator knowledge can be crucial to this part of the process.
Where Does this Information Come From?
Robust risk assessments rely on high-quality data & information, which can come from:
Asset management systems
Maintenance and inspection records
Track inspection and testing trains
Incident reports and root cause analysis
Remote condition monitoring (RCM) systems (more on these HERE)
As remote sensing and data analytics tools improve, so does the quality and granularity of the data available to engineers. This in turn improves the accuracy of risk assessments.
Weighing the Cost of Failure vs. Prevention
At the heart of RBM is a judgement call: is it more cost-effective to prevent a failure or to respond to it?
Some assets—like certain junctions or power supplies to signalling equipment—are so critical that any failure would have massive consequences. These are usually maintained to the highest level, no matter the cost.
Others may have a lower impact. For example, a low-traffic siding might fail without significantly affecting operations. In these cases, a less intensive maintenance approach makes sense.
How Technology is Accelerating Risk-Based Maintenance
The growing role of remote monitoring, machine learning, and AI is making risk-based maintenance more practical and more powerful.
RCM systems can now measure everything from rail temperature and geometry to component wear and vibration in real time. Train-borne systems and drones can inspect assets faster and more accurately than ever. And AI can spot trends and predict failures before they occur.
This wealth of data, when analysed properly, gives maintainers the confidence to intervene only when truly necessary.
Benefits vs Challenges of Risk Based Maintenance
RBM has many benefited, but isnt without it's challenges.
Benefits
More efficient use of maintenance resources
Fewer failures and safety incidents
Reduced downtime and delays
Less unnecessary work
Improved service performance for passengers and freight
The Challenges
High initial costs for data systems and sensors
Continuous effort required to analyse and act on data
Requires consistent and reliable risk assessments
Human judgement still plays a role in determining acceptable risk levels
There’s also the risk of missing rare but high-impact failure modes that weren’t originally anticipated, an issue most common in new asset or equipment types. This makes it important that regular reviews are undertaken and the strategy evolves as more data is gathered.
Summary
Risk-Based Maintenance is not just a buzzword—it’s a critical shift in how we manage complex infrastructure like the railway. By focusing on risk, engineers and operators can make smarter decisions, reduce costly failures, and ultimately improve service for everyone who relies on the railway.
As technology continues to develop, this strategy will only become more effective. And while challenges remain, the direction of travel is clear: a railway that maintains what matters, when it matters.
Want to dive deeper into how railways are maintained in practice? Check out my full video on Risk-Based Maintenance HERE
And if you haven’t already, download my free Guide to Cant PDF – ideal if you’re learning about railway track geometry. Get it HERE
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