Background
Aachen-Eilendorf (Population as of June 2020: 16001) is a suburb of the city of Aachen, located in the federal state of North-Rhine Westphalia in the extreme west of Germany, located 60km/37mi west of Cologne and 4.5km/2.8mi east-northeast of Aachen itself, which lies on the border with the Netherlands.
Eilendorf lies on the Cologne-Aachen high speed rail line, a double-to quad-tracked electrified main line first opening in 1841, being the world’s first international railway line (as it was extended into Belgium in 1843), before being refurbished into today’s configuration in the early 2000s. The line is part of the Trans-European PBKA/PBCA (Paris, Brussels, Cologne, Amsterdam) network for intercity and Thalys trains. The line is used by both national and international passenger express services as well as similarly national and international freight trains along with regional passenger services on connections both within Germany and ones passing into the Netherlands.
The train involved
RB 11958 was a regional passenger service connecting Stolberg-Altstadt with Heerlen (Netherlands). At the time of the accident it consisted of two DB (German national railway) Series 643 which had met up at Stolberg main station. The DB series 643 is a two-car diesel powered multiple unit made by Bombardier Transportation between 1996 and 2008 as the first generation of their “Bombardier Talent”-series. Each unit measures 34.61m/114ft in length at a weight of 89 metric tons. Each series 643 carries two diesel engines producing 315kW/422hp each, which, unusually for modern rail vehicles, directly drives the inner axles of their respective car and allows a top speed of up to 120kph/75mph. The two-part trains (3 and 4-part versions exist also) can carry up to 98 passengers each. Up to four series 643 can run in multi-traction, being controlled from the leading unit’s leading cab.
Leading the double-traction at the time of the accident was 643 224, with 642 225 trailing. The driver of the rear unit chose to remain in his driver’s cab, which now was in the middle of the train. The leading train was running effectively in reverse, with the rear cab car (643 724) leading. At the time of the accident 67 people were aboard the train, including two drivers.
The accident
On the 25th of June 2012 at approximately 10:20am RB 11958 departs Stolberg main station, having been coupled together into a double traction there after the two Talent-units originated in different places. At 10:25am the train has completed its first stop at Eilendorf and is just starting to pull away when the train control system suddenly triggers an emergency stop, bringing the train to a stop rather precisely halfway between two stations at 10:30am.
The driver of the leading unit can’t reach his coworker in the rear unit via the train-to-train intercom, in the meantime the train’s onboard diagnostics system piles on a variety of implausible and partially contradictory errors. In the meantime passengers in the leading unit started to see smoke pouring out of a switch cabinet near the rear control cab. They used the passenger-driver intercom to report as such to the driver, who, at 10:34am, notified the local dispatcher and ordered traffic on the line to be shut down. Over the next few minutes the drivers and conductors assisted the passengers in evacuating the train, collecting everyone on a narrow strip of grass alongside the tracks. 2 people required hospitalization for smoke inhalation, five more were treated at the site.
Aftermath
By the time the fire department reached the site around 10 minutes after being alarmed by the dispatcher flames were licking out the glass-less windows of the rear unit’s leading car, half the rear unit was burning. The heat from the fire got intense enough to snap the overhead wires, requiring another nearby train to be evacuated when it got stranded on open track. By noon the fire was officially declared extinguished, with firefighters entering the burned out train and ripping down ceiling panels to ensure no hidden embers were still smoldering.
Investigators started examining the stranded, burned train in the afternoon, but due to heat and lingering toxic smoke could only briefly enter the interior of the train. Two days after the accident the train was towed to a nearby siding, allowing more extensive examination while the damage at the site was repaired. Due to the nature of the accident (at the time suspected to be accidental fire) specialized investigators for train-fires were involved in the investigation. The statement by the train staff as well as indications in the remains pointed to the switch cabinet near the rear train’s leading cabin as the origin of the fire. Comparing the remains of the burned cabinet to its identical sibling in the other train investigators eventually blamed the origin of the fire on a faulty wiring isolation on the rear unit’s high-voltage positive side and a similar fault in the leading car’s adjacent negative side. This led to a faulty current/short circuit when the two units were coupled at Stolberg main station. The faulty wiring sent an excessive current through inadequate wiring, completely overwhelming the fuses and circuit breakers meant to stop the ensuing chain of events.
As the train powered up and eventually departed Stolberg main station the wires began to heat up from the excessive current flowing through them, leading to a smoldering fire and eventually an open flame consuming surrounding isolation and wires. 10–15 minutes after the trains had been connected and power started flowing through the faulty connection the wiring in the switch cabinet was on fire. Eating away more and more cables the flames disabled one system after another, eventually cutting feedback from the train’s dead man’s switch which triggered the emergency stop. At this point the fire had destroyed the onboard batteries and spread into the roof of the train, dooming the train for good. By the time the fire department got to the site the entire rear unit’s roof was burning within itself.
The report closes with a number of recommendations, but without a definitive person responsible for the fire. After the accident train drivers using the Bombardier Talent in this configuration are ordered to inspect the wires in the switch cabinet for faulty isolation after the end of their shift, as part of the routine checks. Similarly, when taking over a train of this type train drivers now have the right to refuse a scheduled multi-traction if their train carries faulty isolation in the high-voltage area. If faulty isolation is discovered the trains can remain in service at that time, but are to be sent to the maintenance facility for repairs at the closest possible time. After discovering faulty isolation on the high voltage side the affected unit is to be blocked off and not carry passengers until the defect is addressed.
Once the investigation concluded the two affected units were sent off for scrap, one being burned out and the other damaged beyond repair from heat, smoke and firefighting-materials. The first generation Bombardier Talent is still in regular use with the DB and various other European railways, despite being at least 14 years old now. An electric only Talent Mk2 has been introduced into service in 2008, but especially the diesel version of the Talent Mk1 has yet to be replaced.
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