12.09.16
Control of risk at the platform-train interface
Source: RTM Aug/Sep 16
Rail Accident Investigation Branch (RAIB) inspectors Richard Harrington and Stuart Johnson discuss how the risks associated with the platform-train interface (PTI) can be properly controlled.
The station platform is where railway passengers are exposed to the greatest risk of fatal injury on Britain’s mainline railway. The PTI is the boundary between the platform and the train (or track if no train is present).
RSSB recently reported that the overall level of harm at the PTI increased by 48% in 2015-16 compared with the previous year. Most of this increase was driven by four fatal accidents which involved passengers coming into contact with moving trains (none of which were associated with the train dispatch process) and two other accidents which did not involve a moving train.
Focusing on the dispatch process
RAIB has a particular interest in accidents that occur during the dispatch process, since this is an aspect of the PTI where the rail industry can most easily control risk. During the last 10 years we have investigated a total of eight accidents on the mainline network in which train dispatch was a factor (of which one was fatal). These have included dispatch by platform staff (2), guards (2) and drivers (4). In five of these cases, a passenger became trapped in a train door and was subsequently dragged as the train departed. Two of these five ‘trap and drag’ accidents occurred during 2015-16; unfortunately, one of these resulted in life-changing injuries to a passenger.
PTI risk extends beyond the mainline railway. In the last 10 years the RAIB has also investigated four ‘trap and drag’ incidents that have occurred on metro systems (three on London Underground and one on the Tyne and Wear system). The most recent of these was at Clapham South (LU) in March 2015 – resulting in serious injuries to the person involved.
On 22 October 2011 a fatal accident occurred at James Street station, Liverpool. A teenage girl leaned against the side of a train as it was about to depart from the station. Despite the close proximity of the girl to the train, the guard signalled the driver to move off, causing her to fall into the gap between the platform and the train. The guard was subsequently prosecuted and jailed for his actions.
Reviewing PTI risk
RAIB’s investigation report considered the factors that contributed to this tragedy, and reviewed the history of other PTI accidents. As a result of our findings, we recommended that the industry as a whole should provide more guidance on how the risks associated with the PTI can be properly controlled. We observed that operational measures, such as improved staff training, had failed to deliver any sustained reduction in risk at the PTI and that there was a need to consider additional engineering measures.
The James Street investigation, and our investigations since, have led us to some conclusions about the factors that will contribute to safer train dispatch. These include:
- Equipment and methods which enable the person responsible for dispatch to:
o observe the platform/train interface without interruption for as long as possible, ideally until the train has left the platform; and
o stop a train quickly in an emergency
- Adaptation of trains and infrastructure to reduce the size of the platform edge gap when this is possible and appropriate
RAIB is pleased that the rail industry has now established a cross-industry PTI strategy group to review the management of PTI risk, including consideration of station and rolling stock design measures.
Another particularly dangerous situation at the PTI occurs when a person on the platform becomes trapped in the doors of a train, which then begins to move. The design of power-operated doors in the UK has generally relied on soft door edge strips, which permit small objects to be withdrawn, and an interlock which detects the position of the doors and prevents the driver applying power to move the train if a larger obstruction is preventing the doors from fully closing. This means that most current train doors will not detect the presence of small objects such as fingers – a fact that has not been well understood by members of the public, or some railway staff.
The RAIB has also found that the seals on some types of train doors are more prone to trapping small objects than others. It is for this reason that RAIB is urging train operators to examine the feasibility of installing sensitive edge technology, which is capable of sensing contact with a trapped object, into the doors of trains in the Networker family.
Our investigations continue to show the vital importance of the safety check by the person responsible for train dispatch, to confirm that it is safe for the train to depart once the doors have closed. However, since the human being is fallible, and given the growing numbers of passengers on the network, it is important that the rail industry deploys the best of modern technology to address the issues identified by the RAIB over the last decade of investigation.
FOR MORE INFORMATION
W: www.gov.uk/government/organisations/rail-accident-investigation-branch
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