The disastrous derailment in the Gotthard Base Tunnel in August 2023 might have been caused by a systematic problem possibly affecting a great number of wagons running on European railways. The problem seems to be with the more modern brake pads made of composite material, which does not dissipate heat as well as their predecessors in cast iron, causing wheels to crack.
These conclusions come from a leaked draft report from the Swiss Transportation Safety Investigation Board (SUST), obtained by Swiss tv programme Rundschau. The report states that all the wheels of the wagon that started the derailment in the tunnel presented similar cracking characteristics, some older than others.
‘All wheels must be checked’
The issue with the wheels cannot be attributed to a lack of maintenance, but it is rather a systematic issue present in the majority of wagons, experts claimed. The most common braking system is brake pads, which press on the wheel to make it stop. This process might cause heat, especially since now trains are travelling at much higher speeds, requiring more braking power.
Moreover, the newer pads are made of composite, which are less apt at dissipating heat than the older ones made of cast iron. The leaked SUST report also recommends that all wheels equipped with brake pads made of composite materials should be checked. Moreover, they say that maintenance should be radically changed as well, both in terms of cadence and technology.
Many similar cases detected
The commonality of this problem is highlighted by the fact that 77 cases of cracked wheels have been recorded since the derailment in the Gotthard, Swiss media SRF wrote. In 10 cases, the wheel broke. Among the most notable instances is one from November 2024 in Domodossola, northern Italy. One of the wheels was discovered to have a crack by chance during a brake test, causing the immediate halt of the convoy, avoiding significant damages by pure luck.
The derailment in the Gotthard Base Tunnel
The derailment occurred on 10 August 2023 at the Faido interchange. A train operated by SBB Cargo derailed due to a faulty wheel and smashed into the gate separating the two tubes of the tunnel infrastructure. The accident caused over hundred million euros in damages and huge losses for operators, which had to deal with reduced capacity along the main rail axis between Italy and Switzerland for over a year. Initially, one tube of the tunnel was reopened for freight traffic, allowing the transit of around 100 trains every day. For a full reopening of Gotthard Base Tunnel, the industry had to wait until 2 September 2024.