In this article he wrote during his time at Govia Thameslink Railway, Justin Willett, Network Rail’s Director of Operational Capability, considers overspeeding.
We have of course seen the catastrophic consequences of excessive speeding. The accident in Santiago de Compostela in 2013 is probably the most devastating example as it led to the loss of 79 lives.
More recently, at Peterborough on 17 April 2022, a passenger train passed over three sets of points at 75mph. The train lurched sideways. A number of passengers suffered minor injuries as a result. There have also been notable incidents of speeding with no immediate consequence or accident. Is this just luck or by design?
Overspeeding is an obvious concern, especially where it is more extreme. However, the speedo is on the desk and could be considered secondary information under conventional signalling, as normally we get our primary information of movement authority through the windscreen by observing the lineside signals and indications.
Should we then not expect some minor fluctuation, as we don’t want the driver staring at the speedo continually but scanning at regular and appropriate intervals? Is it then acknowledged that between checking the speed it may creep over by 1mph or so?
If it’s noticed and corrected quickly, is this not good driving? Or if this minor exceedance is a worry, does it encourage us as drivers to go deliberately under the permanent speed restriction to give ourselves a margin of error, to avoid the telling off?
Overspeeding is an obvious concern, especially where it is more extreme. However, the speedo is on the desk and could be considered secondary information under conventional signalling.
Yet, in turn, are we robbing the network of capacity, artificially creating a lower speed that extends the restriction needlessly? Or can we drive the design limits of the infrastructure as our competence and experience allows?
How often do these speeding events actually happen? And this includes where the front of train might be slightly over when entering, and the rear of train creeping over on exit. For many of us, the latter is based on our professional judgement of when to open up. Is this just another way of saying ‘best guess’? And should we leave another margin of error before taking power to make sure we’re well clear?
Should we be looking for these minor exceedances of 1-2mph? Should industry be supporting drivers here? Are they really an industry risk?
Significant, regular or sustained exceedances are more of a concern and therefore should the focus be on these, with a deeper understanding of why? What is the risk when it does happen? Does it impact braking distance due to signal spacing, level crossing timings, infrastructure limitations from curves to gauging? And does this change with emergency or temporary speed restrictions. In other words, do we understand the different risks of speeding and where to put the focus?
How much speeding – marginal and significant – actually happens? How much is not reported and only picked up on occasional radar checks and random OTDR analysis? If we don’t report, it stops any further understanding and learning, but does the railway expect self-reporting? If so, what barriers do we need to remove? Do we need a speed exceedance fair culture?
Justin’s questions have been pondered by the OverSpeed Group, a subgroup of the Train Accident Risk Group, since it was formed in light of RAIB’s report on the Laurencekirk and Portlethen incident.
One issue is getting better data to help understand the risk and how to manage it more effectively. The group is working on creating a more risk-based reporting pack.
