Bowties in rail - case studies

24/08/2021

Bowtie models are an ideal means of relating risk controls or barriers to those responsible for implementing, improving or managing them. To date we have helped the rail industry to build bow tie models to illustrate the relationship between risk controls and the hazards they intend to prevent in several key areas including freight derailment, trespass and Covid-19.

The bowtie method can be used in various risk assessment contexts. For example, a company might develop a bowtie analysis to show how they manage a particular hazard in all their stations, linking the control measures or barriers to specific processes and procedures in their safety management system. They might then use the bow tie model as an audit support tool to verify that the controls are being effectively implemented in different stations.

Another example might be their use in understanding an emerging new risk, such as Covid-19 infection of passengers using the trains. This could be used to shape, and direct discussions as new information develops and understanding improves.

It is possible to develop a bow tie following an incident or accident, to understand what actually happened, why things went wrong, and where there might be weaknesses in the safety management or set of controls that we can learn from.

A recent example of using bow tie analysis as part of a Taking Safe Decisions process was a cross-industry investigation of concerns over freight derailment. The development of the bow tie brought together several disciplines, and representatives of different stakeholder companies. The freight derailment bow tie model supports the activities to manage freight risk under the rail industry’s health and safety strategy Leading Health and Safety on Britain's Railway.

RSSB, together with rail industry stakeholders, has developed bow tie models for several risk areas including:

Freight derailments

The freight bowtie risk analysis workshops helped to understand the risks, identify control measures for those risks, and to evaluate the strength of each control. Details of the freight derailment bow tie are available on the ‘Tackling Freight Derailment’ page.
Trespass risk

The industry Trespass Bowtie model illustrates the relationship between trespass risk controls and hazards. Details of the trespass bow tie are available on the ‘Industry Trespass Bowtie’ page.
Slips, trips and falls

The industry’s slips, trips and falls in stations is presented in this bowtie model.
Responding to Ill or Injured Passengers in Stations

The slips, trips and falls bow tie model was used to study responses to passengers becoming ill or injured in stations. Details are given in the ‘Bowtie for Responding to Ill or Injured Passengers in Stations’.
Covid-19

Our Covid-19 bowtie model (simplified view and detailed view) shows the risks from infected passengers at stations or onboard a train.
Augmented bowties

Research conducted to demonstrate that data from a range of sources can inform and improve the bow tie approach to risk management, resulting in an ‘augmented’ bowtie. Details of the augmented’ bow tie work are available on the ‘Development of an Augmented Bowtie’ page.
Train Overspeed

Overspeeding is a precursor to several types of rail accident and can also result in damage to infrastructure and result in injuries to or, in exceptional cases, fatalities. Following on from the overspeed at Sandy South on 19 October 2018, and a subsequent overspeed at Dauntsey on 12 August 2020, RSSB produced the ‘Train Overspeed BowTie Analysis’ report to improve awareness of the hazards, risks and controls around managing train overspeed.
Platform Train Interface

Three PTI bowtie risk models can be used to help understand and improve risk at the platform train interface. They can be used to develop company or location specific bowties, linked to company specific local processes and procedures.

We are in the process of developing bow tie models in other key risk areas in alignment with the Rail Health and Safety Strategy. We are also in the process of developing a BowTieServer library. This is a centralised software that industry users can access online to develop, publish, review, compare and share collaborative bow tie analyses to promote a common, consistent good practice approach.

Currently our bow tie model pipeline includes:

Overspeeding trains
Trackworker safety
Road Risk
Staff Physical / Verbal Assault.