Continuous learning is the way forward on error

9 Jun 22

The importance of knowledge-sharing and transferrable industry lessons were highlighted by Steve Williams from Network Rail at the GIRI summer members’ meeting. In a presentation that focused on what Network Rail is doing to avoid error, he argued that the industry needs to do more to tackle error, underlining his theme by sharing examples of good practice as well as errors.

Being open about what went wrong – so that everyone can learn from it – is critical to enabling improvement. “Error is our downfall as an industry,” he told the audience. 

A mat failure during the movement of a reinforced concrete bridge on self-propelled modular transporters at Gypsy Patch Lane in 2020 was one of the incidents Steve described. Despite the mat sinking eight inches under test conditions, the decision was taken to use the same system under the 5,000-tonne bridge load, with a predictable outcome. 

“Why did this happen? Because the execution was not in accordance with the design,” said Steve. “The design risk assessment clearly expressed the key issues on the drawings. In this instance, the project decided to try to save money by not doing something they should have done. The consequences were millions of pounds lost, a 16-day overrun and reputation damage – all because they ignored a perfectly adequate design and didn’t ask the consultant to review what they were proposing.”

A second example was the collapse of a section of wall on the Nine Elms viaduct in London on Christmas Day 2020 – the timing being the main reason there were no fatalities. Several causes of error were identified on this project, including failure to properly consider of the effects of heavy plant loads on the existing structures and inadequate understanding of the condition of these structures. “How often do we assume everything is fine…because we haven’t done the right surveys?” Steve asked. Lack of coordination between disciplines, and a failure to learn from similar events were also highlighted. 

In August 2021, a temporary scaffold bridge, installed to carry services over the railway while Network Rail renewed another bridge, collapsed at 3am. The two people on it at the time managed to jump clear and again, injuries were avoided. The structure was incomplete when the decision was made to load it, and there was inadequate design and checking, failure to communicate the key design risks, and inadequate application of construction assurance.

The most important reason was that insufficient time was given to properly design, check, assure, and execute the proposals, because of a demand to get it in place quickly. “Error is often created by people who haven’t got time to do the job properly,” he said.

However, it is just as important to share learning when things go right, said Steve, sharing examples of where collaboration and good communication resulted in successful project outcomes.

In the 2021 award-winning Crumlin River Bridge project, Network Rail used safety-by-design principles, early contractor involvement and stakeholder management to deliver the project efficiently and safely and minimise disruption for road users. “By investing in facilitating the proper positioning of the temporary works and the crane, and by considering the whole picture, we achieved a very successful project for all stakeholders.” The Department for Transport described the project as a “model for cost-effective railway enhancement projects”.

Collaboration was also a feature of the Bletchley Flyover project, another successful outcome where innovative engineering techniques were used to deliver £70 million in savings, reduce disruption, and increase the speed of construction. Modern methods of construction, hollow PCC as formwork, and fully integrated temporary and permanent works design at all stages of sequencing were key aspects of this. The permanent works were used to create a physical barrier so construction could be carried out with trains running. “A huge amount of work went into this,” said Steve. “The team designed permanent works to accommodate temporary works, and vice versa, and it was a very successful project with few errors.”

He then went on to outline the strategies Network Rail uses to avoid error and fulfil its mission to bring everyone home safe every day. “We work collaboratively as one team, and we communicate openly. We follow procedures, standards, and guidance – these are there for very good reasons.”

Network Rail closes out assumptions as designs develop, and ensures they are fully developed to Approved for Construction status before execution. “We need to give people time to get to AFC so we can get to a design that can be built rather than doing it the other way around.”

Other strategies include checking permanent works and temporary works sequencing and ensuring interfaces have been fully agreed and checked; contingency planning; provision of a specification, supported by inspection and test plans; site supervision by appropriately experienced persons; ensuring all risks are appropriately assessed, mitigated, and controlled; and executing the works in accordance with the design, with the designer agreeing to any significant change. 

“We need to embrace the concept of designers and contractors working together as a team,” said Steve. “And we need to focus on disseminating both lessons learnt and good practice, internally and externally, for the whole industry’s benefit. In other words, we need to foster a culture of continuous learning without apportioning blame. This the way forward.” 

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