Today, more people travel by rail than at any point since the 1920s. However, such growth in popularity is resulting in significant pressure to ensure the network can cope with this demand. With an ageing infrastructure and fleet, maximising reliability has become one of the biggest challenges for the industry.
Investing in new trains isn’t always the answer. Not only can the cost be prohibitive, but the sophisticated technologies that now come with a new fleet can introduce complexity with greater opportunities for system failures to occur. In fact, recent moves to bring Class 20, 37 and 47 locomotives back from preservation or storage to mainline service demonstrates that, with the right maintenance, assets can continue to perform long beyond their design life.
If investment is to be made in new rolling stock, addressing the importance of reliability within the design phase is crucial to minimising the opportunities for failures.
Reliability initially comes from the design and build quality. If the initial design is good then it stands to reason that the equipment will be reliable, providing that the design is translated into a good build by ensuring that good quality materials that meet the appropriate standards are used. Furthermore, during service, reliability will not be retained at its inherent level unless appropriate preventive maintenance is carried out.
There are two main types of maintenance. Preventive maintenance is carried out at a chosen time when manpower, facilities and spares are readily available. This should ideally represent approximately 80% of all maintenance activity.
The remaining 20% is corrective maintenance, which may require a train to be recovered back to depot and a replacement train brought into service. This is likely to also attract penalty minutes and maintenance that must be carried out when manpower, facilities and spares are not readily available.
Getting the balance right is key to ensuring optimum maintenance – the most reliable train will be the most cost-effective to run.
One unexpected faulty train that needs to be recovered can quickly result in corrective maintenance costs escalating. Unreliability can also have an impact on reputation, if a company has experienced ongoing reliability issues then it is likely to be more difficult to re-lease these trains at the end of the current lease.
Alternative maintenance regimes
Reliability-centred maintenance (RCM) is a process to ensure that systems continue to do what their users require in their present operating context. It is generally used to achieve improvements in fields such as the establishment of safe minimum levels of maintenance. Successful implementation of RCM will lead to an increase in cost effectiveness, reliability, machine uptime, and a greater understanding of the level of risk that the organisation is managing.
A full strategic maintenance review (SMR) should be conducted when it is considered that the existing preventive maintenance is inappropriate and possibly carried out at inappropriate intervals.
This is likely to be the case where no recent thorough review has been recently carried out (within the last 10 years). One such example is the Class 91 locomotive fleet where RCM was applied. This allowed the fleet owner to double the reliability and remove one heavy repair from the life cycle of each locomotive. Notably, this is a time-intensive activity which provides potentially strong benefits but does take longer to complete and, in turn, reap the benefits. It is necessary, however, if a change to the overall maintenance strategy is required.
Alternatively, a performance improvement programme (PIP), which helps to address the known faults and reduce maintenance costs quickly, may be carried out. A PIP should be conducted when the existing preventative maintenance is considered to be adequate but there is poor reliability. This approach will identify the key systems responsible for the poor reliability and identify improvements by reviewing operations, preventative maintenance (system RCM analysis) and modifications.
A PIP enables the benefits of RCM to be obtained without the time consuming full RCM or SMR requirements, providing results quickly. This may be considered where the fleet is small and the available budget to make improvements is limited. A PIP is carried out using the following steps:
» Analyse failure data to identify the worst performing systems/equipment;
» Investigate those systems looking at any operational issues involved, carrying out RCM and making recommendations for modifications (in that order of priority);
» Identify changes necessary and implement them.
Both of these approaches involve a robust, structured and auditable process. BMT has worked at all levels in the rail industry, alongside both train operating companies (TOCs) and rolling stock operating companies (ROSCOs), in the UK and abroad. The company played an instrumental role in writing the original UK National Fleet Reliability Improvement Programme (N-FRIP), the Twenty Point Plan Document (CR/TP1203) for the Association of Train Operating Companies (ATOC), and continued to support the latter until Issue 2.
Through asset optimisation, BMT assists its clients in developing optimal solutions by analysing designs – focusing on improving reliability and availability. Availability is analysed and increased by formulating and delivering optimised maintenance strategies at vehicle and fleet levels.
BMT delivers maintenance optimisation for clients by developing the most cost-effective and worthwhile preventive maintenance regime for rolling stock and associated equipment using an approach utilising knowledge and expertise gained in other industries. In particular, the use of RCM, a methodology originally developed in the aerospace industry, has allowed BMT to achieve substantial benefits for its rail clients. For example, one fleet of electric locomotives showed a significant improvement in reliability performance coupled with a 30% reduction in preventive maintenance workload.
A further example of how BMT has helped to further improve maintenance planning and thence achieve optimised availability and operating costs is its work with VIA Rail Canada. Focusing on the train operator’s newly refurbished fleet of GPA-30H locomotives, BMT recently carried out an RCM analysis of the locomotive and its sub-systems including the newly-installed head-end power generating set. One output of the RCM study was to identify and add to the condition monitoring procedures and techniques that are currently used by VIA Rail Canada, in order to develop an optimised condition-based maintenance strategy.
Bob Becker, director of technical services and chief engineer for VIA Rail Canada, commented: “BMT’s customer-focused approach, from initial study to final report, places VIA Rail on the correct track for optimised maintenance procedures, cost-effective condition monitoring techniques and our ultimate goal of full condition-based maintenance. The initial recommendations have already produced significant cost reductions for the generator set overhauls, with more locomotive savings to come in the future.”
BMT is also working with a new DMU fleet which is in the process of utilising RCM to help extend Level 1 – Level 4 maintenance and it has been estimated that the customer will secure a 33% saving on maintenance costs each year.
By using techniques such as RCM, train owners and operators can improve reliability and reduce maintenance costs. In the face of ever increasing demand for a reliable service, it’s easy to see why maximising the reliability of the UK’s rolling stock fleet must remain a top priority.
Written by Art Couper, senior consultant at BMT Reliability Consultants Limited, a subsidiary of BMT Group Ltd.