Investigation of the runaway maintenance machine incident in Ylivieska, Finland, on 28 June 2017 – Safety recommendations for the prevention of similar incidents
The safety investigation by the Safety Investigation Authority, Finland, of the maintenance machine that rolled away from a trackwork site in Ylivieska on 28 June 2017 has been completed. The Safety Investigation Authority gives safety recommendations for accident prevention and improvement of rail traffic safety.
The incident involved a maintenance machine forcing open a turnout leading from the work site to a track section used by traffic, and rolled north on a track used by traffic for a distance of one kilometre, coming to a halt at the Ylivieska station. Only moments before, the track section had been used by a freight train heading south. Furthermore, passenger trains were on their way to the station from both south and north.
The maintenance machine rolled off after its pneumatic brakes released because the parking brake had not been engaged and no stop blocks had been used to ensure that the machine stays in place. There was no clear distribution of critical duties for the machine, and critical operations – such as engaging the parking brake – were not verified when leaving the machine standing. In addition, the linkage of the machine's brake system was worn and poorly adjusted. These deficiencies had not been detected during the traffic worthiness inspection and safety inspection conducted on the machine one month earlier.
Recommendations for improving rail traffic safety
The Safety Investigation Authority issues the following recommendation: already at the competitive tendering phase for the project, the Finnish Transport Agency should require each main contractor participating in track projects to have its own safety management system that takes the special characteristics of the companies and work sites into consideration, and include monitoring of the realisation of these systems as part of its auditing process. The main contractor’s safety management system must take the safety objectives set by the Finnish Transport Agency into consideration also with respect to subcontractors.
The Finnish Transport Agency did not require the contractors participating in the track project to have their own safety management systems; instead, it required the application of the Finnish Transport Agency's safety management system. The adoption of the system on a work site with several contractors and subcontractors was deficient, as was the monitoring of the adoption process.
Secondly, the Safety Investigation Authority issues the following recommendation: the Finnish Transport Agency should add instructions to the safety instructions for track maintenance and the rail traffic and shunting work safety rules on the locations where rolling stock may be left standing and the required procedures to ensure it remains in place.
The instructions currently in use do not pay attention to the stand locations and the related procedures for rolling stock. In this respect, the missing instructions give the operators free hands in where and how to leave rolling stock standing, which may at worst lead to a serious accident. The instructions are particularly important in the case of maintenance machines, as their movements and locations are not known by the centralised traffic control.
Thirdly, the Safety Investigation Authority issues the following recommendation: the Finnish Transport Agency should update the Railway Engineering Guidelines so that the section of a switch that sees traffic installed on a track section used by traffic must always be connected to the track circuit of the railway safety system as its own element and connected to the centralised traffic control monitoring immediately when technically possible.
In the worst case, the inability of the centralised traffic control to see switches installed in a track section used by traffic and their incomplete connection to the railway safety system could have caused a serious accident if the maintenance machine had stopped in the switch section. Furthermore, the inability of the the centralised traffic control to see the turnout caused a significant slow-down to the post-incident track inspection operations.
A switch on a track used by traffic should always be visible in the the centralised traffic control system so that the traffic controller is able to locate the switch. The visibility of the switch to the the centralised traffic control also improves trackwork safety, as the turnouts and their numbers are carefully specified in the trackwork notifications.
The Safety Investigation Authority also recommends that the Finnish Transport Safety Agency specify in more detail the checks required during a traffic worthiness inspection as well as the qualification and independence criteria for the party conducting the inspection.
At the time the incident occurred, the brake system of the maintenance machine was worn and poorly adjusted despite a Finnish Transport Safety Agency traffic worthiness and safety inspection that had been conducted on the machine before it was taken into use. At the request of the Finnish Transport Safety Agency, extensive tests and measurements had been performed on the machine, analysing the characteristics of the machine type, despite the fact that the machine type has been used in Finland for over 20 years, now. The purpose of these tests remains unclear, as the visibly poor condition of the individual machine was not detected. One factor could have been the missing of the machine's maintenance documentation. The role of the party that conducted these inspections was unclear in the investigated incident, as the company also participated in the refurbishment of the machine.
The Safety Investigation Authority recommends that the Finnish Transport Safety Agency ensure the implementation of the above-mentioned recommendations.
The on-site monitoring of compliance with trackwork safety regulations should be further increased.
In addition to the new recommendations, the Safety Investigation Authority reiterates the recommendation issued after investigation R2013-02, according to which the Finnish Transport Agency should support the on-site monitoring of compliance with trackwork safety regulations by assigning sufficient resources for this purpose.
Instructions issued by the Finnish Transport Agency define the parties' responsibilities and tasks related to the safety of railway operations, such as trackwork. The instructions emphasise monitoring that has been defined to be primarily carried out in the form of written forms and reports. Work site monitoring is rarely performed on-site with the exception of separate inspection visits.
Further information:Chief Safety Investigator Esko Värttiö, tel. +358 (0) 2951 50708