What would a railway without low adhesion look like?
Being able to stop trains reliably and predictably under a variety of adhesion conditions can deliver operational benefits, but it is also a vital aspect of being able to run trains closer together; safely. ADHERE is an enabler for helping industry to achieve this aspiration, which will ultimately help to increase capacity on the network. It will also provide a key contribution to ensuring disruption to train services is minimised, helping to improve the experience of rail passengers.
Around two-thirds of Train Operating Companies (TOCs) currently implement an autumn timetable, which affects around 10% of all services. Seasonal timetable changes typically include alterations to train start and end times, rather than to service patterns, and the cost is around £11m a year in 2016 prices. The GB rail industry also encountered an annual average of 350,000 adhesion delay minutes over 2010 to 2016. The cost of this autumn performance dip is estimated at around £275m each year when the indirect cost to industry and wider customer and societal disbenefits are taken into account.
Low adhesion is also a significant barrier to increasing capacity. In particular, as we refine the capability of our train control systems through the deployment of ETCS, there is the need to improve the reliability of our train braking systems in parallel. Many of the aspirations for high frequency, reduced headway running that the deployment of Digital Railway technologies offers will be compromised, or just not possible, if we do not improve the predictability of the brake rates that trains will deliver in all adhesion conditions.
Low adhesion problems can result in a range of safety risks, including signals passed at danger and station overruns. Over the period from 2010 to 2016, on average every year there have been 6 adhesion-related Category A4 SPADs; 76 adhesion-related station overruns, and 117 adhesion-related wrong side track circuit failures.
Given the importance of ensuring the safe running of trains and to minimise delays, the rail industry invests £49m each autumn to mitigate and manage low adhesion problems. This investment includes the capital and operational costs of rail head treatment trains, traction gel applicators, manual rail cleaning and lineside vegetation management. By developing deeper insights into the causes of poor adhesion, improving current mitigation strategies and looking into new solutions, the industry could make significant progress toward its high-level goal of enhancing customers satisfaction, reducing costs and increasing capacity.
- Autumn timetables
- Autumn performance dip
- Capacity increase
- Predictable braking
- Rail head treatment cost