Fishbone has worked closely with Porterbrook Leasing Company and South Western Railway to investigate maintenance optimisation on legacy fleets. Significant operational and financial benefits were achieved on the Class 458/5 fleet by extension of the C4 overhaul mileage.
Fishbone was asked by Porterbrook to develop a methodology to evaluate the existing C4 overhaul, and through a risk-based process and trial running, recommend and gain approval for achieving a significant mileage increase between C4 overhaul periods.
Fishbone delivered a 120,000 mile C4 overhaul increase by:
- Reviewing current C4 component maintenance and condition at overhaul.
- Establishing a safe, monitored mileage extension trial
- Reassessing component condition at extended mileages and presenting a case for extension based on expert condition assessment and mitigations
- Overhaul maintenance tasks were reviewed for suitability to run to extended mileages themselves based on unit maintenance histories and failure modes
- A controlled programme of trial running was conducted to ascertain any requirements for change to wear limits, component inspections, and task periodicity
- Proposal for changes to C4 periodicity was presented to the TOC / ROSCO supporting the changes and other interventions required to optimise the overall benefit
- The fleet was certified to run extend mileages for both regimes
- The C4 overhaul periodicity was increased from 600,000 miles to 720,000 miles
Fishbone has successfully completed similar on other fleets for Porterbrook and SWR and are currently undertaking a series of maintenance optimisation reviews for Porterbrook to optimise C6 overhaul either as wholesale maintenance regime change or extended, reduced scope C6 periodicity.
