Background
Latsch (pronounced “Latsh”) is a town and municipality of 5255 people (as of 2020) in the extreme northern part of Italy, located in the Province of South Tyrol 39km/24mi west-northwest of Bolzano and 41km/26mi southeast of the Austrian town of Nauders where Switzerland, Italy and Austria intersect (both measurements in linear distance).
The town lies on the Vinschgau railway (“Vinschgaubahn”), a 60km/37mi long non-electrified single-track branch line originally opening in 1906. The line was used exclusively for occasional regional passenger service from the 1930s before being retired by the FS (Italian national railway) in 1990. Lengthy protests by both locals and tourism-groups got the line overhauled and reopened by 2005, now served by SAD, a private public transportation provider from Bolzano. The line is nowadays exclusively used for regional passenger services, with trains navigating gradients as steep as 2.9% while other sections see trains reach as much as 100kph/62mph.
The train involved
SAD R108 was a regional passenger service from Mals to Meran, carrying a crew of 2 and 35 passengers at the time of the accident. On the day of the accident the connection was provided by ATR 100–007, a third-generation Stadler GTW 2/6. The GTW (“Gelenktriebwagen”, “Articulated rail car”) 2/6 is a three-car multiple unit powered by electricity or diesel engines depending on configuration. The third-generation diesel-engined version started service with SAD in 2004. Each third-generation Stadtler GTW measures 39.5m/130ft in length at a weight of 66 metric tons (diesel-version) and can carry 104 seated passengers along with 110 standing ones in the configuration of number 100–007. The diesel-version has a top speed of 140kph/87mph. The GTW-trains are easily identified by their short middle car (referred to as a “traction module”) which holds the entire traction-system, pushing/pulling the unpowered passenger-carrying end cars on either side of it.
The accident
On the 12th of April 2010 R108 is passing through Latsch station at 9:00am on its eastbound journey to Meran leaving the town on its eastern side the rail line hugs the southern bank of the Adige, a small river that cut a deep valley into the landscape. The rail line runs halfway up the southern side of the valley, with the water below it and agricultural land up above, being separated from the former by a thickly wooded strip.
The train is barely 700m/2300ft past the edge of town when the leading car is struck by landslide on its right hand side, pushing the lead car off the tracks and breaking several windows. The leading car crashes through several trees, obliterating much of the driver’s cab, before becoming stuck in the trees, keeping it from falling into the rapids of the river below. The entire train is derailed, with the rear car remaining somewhat aligned with the tracks while the leading car’s remains hang down the side of the mountain at a severe angle. The driver and eight passengers die in the accident, all remaining 28 people on board are injured.
Aftermath
The first responders reached the site a few minutes after the accident, making their way along the rail line from Latsch. Anchors were attached to the side of the valley to secure the train against falling further down the valley, only once that danger was handled could responders start rescuing the survivors and recovering the victims.
It was clear fairly soon that the train’s condition and its driver’s behavior played no role in the accident. Everything related to the train had been in perfect working order, and even if the driver saw the landslide break lose at the last second there was nothing for him to do that would’ve kept the train from being struck. The Stadler GTW fulfilled the highest crash-safety standards at the time, but those structures just weren’t set up to several tons of rocks and soil hitting the train’s broadside and forcing it off the tracks. Plus, similar to accidents with cars, hitting a slim obstacle like a tree poses a very different risk of challenges compared to impacts on a wider obstacle like another train, which is what crash protection development in trains focuses on. Slim objects are not a priority, neither are, somewhat understandably, side-impacts at about 90° to the direction of the train’s motion.
The main questions now where how the landslide could happen on a dry summer day, and why the catch-fences above the rail line hadn’t stopped the soil from reaching the tracks. The latter question was soon answered, when experts pointed out that the fences simply weren’t designed to stop the whole hillside from moving. In the case of the accident of approximately 400m³/14126ft³ of mud, soil and rocks detached from the hillside on a length of 10m/33ft just as the approached, reaching the tracks just as the train was passing the site. An engineering-magazine which covered the accident cited Professor Richard Chandler, a British geotechnical engineer, who explained that the fences at the site were set up to catch rockfall, “the occasional boulder”, not several tons worth of soil at once. A main difference apart from the size of the debris (the mud can move through the fence, larger rocks can’t) is the motion and affected area. Rocks falling down a hillside create high-velocity but very localized impacts, while landslides move slower with forces pushing on the fence in a larger area. The fences failed to avoid the accident because they weren’t really meant to, while the retaining wall next to the tracks is designed to hold back soil and did so, with the landslide moving over the top of it.
The big question that remained was how the landslide could have happened in the first place. Investigators examined the area where the landslide originated, and stumbled over a broken irrigation pipe at the edge of an apple orchard at the top of the hillside, right next to where the landslide had started. The small pipe measured just 65mm/2.6in in diameter and had been constructed to bring water out to the far end of the rows of apple trees. Closer examination of the piping led to investigators finding a faulty valve near the origin of the landslide, which had caused water to leak from the pipe into the surrounding soil. This condition had been present since before the accident, while the investigation found no sign that the pipe had burst at a point prior to the landslide. As such it was concluded that the water leaking from the faulty valve had slowly saturated the soil below the surface, reducing its stability, until, eventually, gravity pulling on the inclined soil had overcome the muddy layer below and pulled the upper layer of soil down the hillside and onto the train tracks. By tragic coincidence this happened just as R108 passed the site.
Bolzano’s public prosecutor filed charges against eight individuals following the investigation’s conclusion, six were from the company in charge of the irrigation system in the area and two were the owners of the property where the fault had occurred. Six of the eight individuals were put on trial in January 2013 for charges surrounding dangerous interference with rail traffic and negligent cause of bodily harm and death respectively. The trial ended in November 2015 with all defendants being relieved of criminal guilt, with the court deciding that the leaking valve going unnoticed was such a minor defect that nobody could foresee the consequences it went on to have, and thus there was no criminally relevant responsibility lying with any or all of the defendants.
The rail line had been repaired within two months of the accident, and a year after the accident a memorial was unveiled along the bike-path on the opposite side of the site. The path of the landslide remained easily visible after the accident in the form of a wide gap in the vegetation, photos from Summer 2022 show that that gap is starting to close.
The train involved in the accident, ATR 100–007, was damaged beyond repair and pulled from service after the accident, serving as a parts-donor for the company’s remaining fleet of identical trains. The train line is equipped with a system to detect landslides and stop approaching trains automatically, the system couldn’t avoid the 2010 accident since the landslide hit the train directly rather than creating an obstacle for the train to run into. There is no real direct solution to the cause of this accident, apart from trying to catch the originating issues with closer inspections. Making windows significantly harder to break is counterproductive, since this would make the rescue of passengers after an accident much more difficult. This issue was glaringly present during the 1998 Eschede train derailment, after which the breakability of windows was improved so that responders didn’t need powerful cutting-tools to access the interior of the trains.
The Stadler GTW received an upgraded fourth Generation before being replaced whole with the Stadler “Wink” in 2017, which fulfills even higher crash-protection standards than the GTW did. The trains feature a more angular front end design but retain the distinctive short traction module in the middle. Having been made over 600 times a lot of GTWs are still in service in various countries including Germany, Switzerland and even the USA, and they’re unlikely to disappear from service anytime soon.
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A kind reader has started posting the installments on reddit for me, I cannot interact with you there but I will read the feedback and corrections. You can find the post right here.
