Comment

Safety of technical systems: the next 30 years

George Bearfield, visiting professor of railway system safety at the University of Huddersfield and director of health and safety at Rock Rail, takes a look at how the rail industry can future-proof its systems for the coming decades.

Railway systems, like rolling stock and signalling systems, are highly complex, heavily bespoke systems, and their renewal is a huge investment for the industry. Because of this, they generally have to last a very long time: sometimes 30 years or more, as we may note, while finally saying goodbye to British Rail Class 43 HST.

When introducing new equipment, we need to look far ahead and think about how it is going to function – cost-effectively and safely – far into the future. The railways are part of society, and society, as well as technology, evolves in fundamental and sometimes unexpected ways over such timeframes. If we go back 30 years to 1989, the world was very different. The iron curtain was only just falling and Section 28 was passed as an amendment to law, putting LGBT rights in a very different place than today. And significantly for the railway, rail accidents were unfortunately a regular occurrence. 

We have just seen the 30-year anniversary of the accident at Clapham Junction where a maintenance error caused a false proceed aspect, a three-train collision, and the deaths of 35 people. The following year, six more people were killed in the Purley Rail crash when a driver passed a signal at danger. At the time there were no automatic train protection systems in place across the network. Mark 1 rolling stock, which was not crashworthy, was hurtling around the infrastructure. These things would not be addressed until the aftermath of the Ladbroke Grove rail accident 10 years later. And there were other risks: fires on trains were common place, with vehicle interiors that were flammable. Cigarette smoking on trains would not be banned for commuter services for another year.

So, in building trains and other technical systems for the next 30 years, we need to recognise that they will need to fit with significant change in society and its expectations. We should expect increasing demands around decarbonisation, accessibility, comfort, and service. As regards to safety, it is important to recognise that it is now 12 years since the occurrence of a fatality on a train due to a derailment or a collision. This is a great record, but it comes with a challenge: the public, now and into the future, do not expect and rightly will not tolerate the occurrence of accidents like those of which we saw in the past. 

The combination of changes we will see in digital technology, safety, and security might also combine in other interesting and challenging ways. The renewal of the traditional railway with modern digital systems is a significant opportunity, but needs to be done in a way which recognises that the safety of the railway we know today has been built on the knowledge and experience we have with fundamentally different technologies. The traditional railway was electro-mechanical and people-based. The front line staff operating the networks knew how it worked: it was transparent to them. Staff could use their own experience to improvise when things weren’t going quite right. Accidents happened occasionally and were learnt from to improve.

Modern railway equipment is increasingly delivered using software, as more of an opaque ‘black box,’ and railway functions are more automated. We will need to find a good way to embed local railway knowledge into system requirements, even when they are designed and built in the global supply chain – a long way from the railway they will be integrated into. Given that we expect new technology to fail rarely, we will also need to consider how the local users can diagnose any rare and unusual faults and manage them. In approval and operation, there needs to be some form of ‘design for transparency’ so that those that ultimately own the risk can assure themselves of system safety.

The UK railways’ good safety record makes it an outlier amongst our peers in Europe. This safety performance has been built on a culture of openness and transparency.  However, for entirely understandable reasons, security concerns create a drive towards being less open about the ways in which systems can fail dangerously. This is a problem to be dealt with cost-effectively in system design, safety, and security, as they need to be considered together with coherent defences built by the same people at the same time. Commercial sensitivities can also drive a more closed culture, as the investment needed to improve the railway needs to be worthwhile and to pay back to investors. Squaring these challenges with the need for openness and transparency to maintain our safety culture and assurance will, in my belief, be a theme of the coming innovative era too.

The positive note to finish on is that the third industrial revolution that is underway creates an almost infinite amount of possibilities for innovation to drive better outcomes all around – so every challenge has a multitude of possible solutions.  As one simple example, work undertaken recently at the University of Huddersfield on the use of various real-time or near real-time data sources to monitor the safety of the operational railway creates a possible solution to some of the challenges raised here. The approach could be used to develop a watchdog of how dependably railway equipment delivers the safety critical functions that it is required to. 

Such an approach would be genuinely diverse and agnostic to how the system had been designed, therefore meaning that it could provide a defence against both safety-related design errors and security threats, reducing cost and improving integrity. The final lesson from the past is that the changes here and others are inevitable, and those that embrace them will be the ones leading the way for the future railway.

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