RSSB reaffirms DCO
A new report confirms there is no safety reason to prevent further adoption of Driver Controlled Operation on the network.
THE Rail Safety and Standards Board (RSSB) has said that “There is no safety reason to prevent the further adoption of Driver Controlled Operation (DCO)” in a report into the practice issued on June 14.
The report concluded that DCO trains pose a lower overall dispatchrelated passenger safety risk, and that analysis implied there would be no additional assault risk for passengers on DCO trains.
“These trains appear to be lower risk,” it said, adding, “If the conductor/auxiliary person has a benefit in reducing on-board assaults, it is small compared to other factors influencing this risk.”
On the subject of the uncontrolled evacuation of DCO trains, the RSSB said the risks were small, and of a similar level to those with conductor operations.
However, the body confirmed that when protection of the line in an emergency is considered, the presence of a conductor does provide a safety benefit. Much of this, the report claims, is due to a conductor being able to operate GSM-R radios, rather than applying track protection measures such as track circuit operating clips, and that an auxiliary person trained to use the emergency functionality of GSM-R would provide almost the same benefit.
“The benefit is small and is smaller than the knock-on risk from cancelling the train if the auxiliary person was unavailable,” it said.
In the report the RSSB made two recommendations. The first is that train operators should consider training the auxiliary person to use the GSM-R radio in an emergency and that if the auxiliary person is unavailable, the train should continue in service as Driver Only Operation (DOO), “as this option is the lowest risk overall.”
The second recommendation is that the RSSB should review the requirements for emergency protection to ensure that the rule book requirements manage the risk from secondary collision effectively.
The report examined the risk for various aspects of rail operation and concluded that the overall risk from mainline rail operations (excluding suicides) is 132 fatalities and weighted injuries (FWI) per year. The risk from the platformtrain interface is estimated at 13 FWI and from train dispatch at 1.8 FWI. Train accident risk is around 7.9FWI, and secondary collisions 0.47FWI. Onboard assaults by passengers on other passengers accounts for 4.5 FWI per year.
The RSSB examined the dispatch risk for areas including injuries while boarding or alighting a train, coming into contact with a train while on the platform, falling between the train and platform and Signals Passed at Danger when starting against the signal (SAS) at platforms. It concluded that in metro and suburban operations the
FWI per billion journeys under DCO was slightly lower than conductor dispatch – 0.87 against 1.19 – while for inter-city conductor operations it is more than 2 FWI/ billion journeys. It suggested this could be because passengers on commuter routes may be more experienced and familiar with the way the trains are operated and therefore less likely to have an accident. Additionally, it suggested that passengers on inter-city trains may have more luggage and thus be more prone to accidents at the platform-train interface.
In terms of protecting the line in an emergency, on trains where the driver has sole responsibility the FWI per billion train-km is 1.24, compared to 0.79 on trains with a conductor and 0.85 on those with an auxiliary person trained to use the GSM-R radio in an emergency.
The RSSB said it believed that 90% of the benefit of having a conductor in such circumstances comes from their use of the GSM-R radio, rather than their placing track protection. If no auxiliary person is available, the RSSB’s conclusion that trains should run under DOO as it is safer than cancelling a train is based on a number of factors, including the ‘knock-on risk’ from increased boarding and alighting and potential crowding on platforms; slips, trips and falls due to turning trains around en route; extra station dwell time; crowding and changes of platform; and increased risk of staff assault because of passenger frustration during delays and cancellations. This knock-on risk is calculated – in terms of the increase in millionths of FWI per day – as being around six times higher when cancelling the train rather than operating under DOO.
On the issue of onboard assaults, it said the risk on DCO operations is 2.2 FWI per billion journeys, while the average for conductor operations is 3.3, with higher figures for inter-city and regional operations than metro journeys. However, the report acknowledged: “It is not tenable that the presence of a conductor has a detrimental effect on the risk from assaults.” It pointed out that there could be regional variations in the rate of assaults and reporting and that train operators with restrictive alcohol policies have lower rates of assaults than other operators. It added that, while a conductor may have a positive effect, it is small compared to other factors that influence the rate of assaults.
For uncontrolled evacuations of passengers, the FWI per billion journeys was virtually identical under DCO and conductor operation, although the report admitted that there are insufficient numbers of such events to draw definitive conclusions. “The risk to passengers from uncontrolled evacuations is small and there is no evidence that the presence of a conductor or auxiliary person makes a significant difference to the rate of uncontrolled evacuations,” it said.