Risk of derailment of heavy freight trains – action required

Lo­ket till ett gods­tåg och förs­ta vag­nens främ­re bog­gi spå­ra­de ur norr om Tam­mer­fors sta­tion 30.11.2023. Även om olyc­kan inte or­sa­ka­de per­son- el­ler mil­jöska­dor, or­sa­ka­de den sto­ra ska­dor på väx­eln och be­ty­dan­de tra­fik­stör­ning­ar un­der ti­den 30.11–3.12.2023.

The accident was the sum of many factors: the worn switch or, more specifically, one part of the switch, the high lateral forces to the rail typical of the locomotive type, and the worn wheelsets of the locomotive all contributed to the accident.

The investigation revealed essential safety deficiencies related to rail safety:

• The switch had worn down to its critical maintenance threshold. While this deviation had been observed, the track maintenance operator did not respond to it, as there were plans to renovate the railway yard.
• Supervision by the authorities only targets the safety management systems (SMS) of individual actors at the document level. Issues requiring cooperation between several stakeholders are easily overlooked.
• The instructions on the maintenance of switches are not clear.
• The impacts of the locomotive structure on the track were verified with measurements, but no measures were taken to correct them.
• The wheels of the locomotive were worn nearly to the point of being unfit for use.

“It should be emphasised here that there is a present and possible threat of the derailment of six-axled diesel locomotives, such as the locomotive in this accident, used in freight traffic. We are talking about 18 locomotives at national level. However, they are constantly moving on the public rail network. Derailment may also pose a risk to other users of the railway network,” stresses Lasse Laatta, Investigator in Charge.

The Investigator in Charge continues: “The investigation shows that the operating model based on railway safety management systems (SMS) and self-monitoring is not sufficient, and concrete risk management measures are needed. The measurements and inspections carried out during the investigation show deviations affecting safety that have been revealed in the investigation. The track and the rolling stock using it must be compatible and thresholds for their compatibility must be clearly defined, taking into account their combined effect. The inspection and maintenance of switches must go hand in hand. Clear thresholds must also be set for maintenance. Ultimately, we are dealing with overall safety management, for which cooperation between the infrastructure manager and operators is essential.”

As a result of the investigation, the Safety Investigation Authority issues four recommendations that address the thresholds and measurement methods of switch maintenance and inspection, track maintenance, rolling stock wheel inspection and maintenance, and cooperation between railway network operators in risk management.

“Finland has an extensive rail network. A lot of people as well as goods travel on tracks. Therefore, rail transport plays an important role from the perspective of society – and also the security of supply. The current strategic situation also increases the importance of tracks and the rolling stock travelling on them. We simply cannot afford long traffic interruptions – or worse, the loss of life. We can learn from the causes accident – if there is a will,” adds Kurt Kokko, Executive Director of the Safety Investigation Authority, Finland.