What Would a Railway Look Like Without Low Adhesion?
Being able to stop trains reliably and predictably under a variety of adhesion conditions can deliver operational benefits. It is also a vital aspect of being able to run trains closer together, safely. ADHERE is an enabler to help industry achieve this aspiration. It 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 half 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. The cost is around £8m a year at 2016 prices. The GB rail industry also saw an annual average of 380,000 adhesion-related delay minutes from 2015 to 2018. The cost of this autumn performance dip is estimated at around £280m each year when the 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 with ETCS, we also need to improve the reliability of our train braking systems. We must improve the predictability of the brake rates that trains will deliver in all adhesion conditions. Without this, 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.
Adhesion problems can result in a range of safety risks, including signals passed at danger and station overruns. In the years 2010 to 2016 there have been, on average: 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 around £65m 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 customer satisfaction, reducing costs, and increasing capacity.