Down from the Heavens: The 1924 Ludwigsstadt (Germany) Train Derailment
Background
Ludwigsstadt is a town of 1509 (as of 1925) respectively 3306 (as of 2021) people in southern Germany, located in the far north of the federal state of Bavaria 117km/73mi north of Nürnberg and 60km/37mi south-southeast of Erfurt (both measurements in linear distance).
Ludwigsstadt lies on the Franconian Forest Railway (Frankenwaldbahn), a double-tracked electrified (since 1939) main line opened in sections until October 1885. It forms part of a main railway corridor connecting Berlin with Munich and is named after the local, heavily wooded mountain range. The line sees everything from regional passenger trains and intercity services to freight trains, with some sections of the line being so steep that even nowadays heavier trains need a “banking locomotive” pushing the trains up the inclines as the locomotives up front would be insufficient.
Approaching Ludwigsstadt from the south sees trains pass over the Trogenbach-Viaduct (Trogenbachbrücke), a 200m/656ft long 26m/85ft high bridge taking the rail line over the Trogenbach, a small creek lined with residential housing. The southern section of the Bridge consists of four stone arches, followed by three steel truss sections, each 14.5m/48ft in length, with another stone arch completing the support structure. The bridge was built between 1883 and 1885, and the mixed construction was chosen as the town was difficult to access for large vehicles, making it easier to construct part of the structure out of bricks.
The train involved
EGz 6143 was an express freight service travelling northbound on the Franconian Forest Railway, consisting of a locomotive and 27 freight cars of different kinds. It was staffed by a driver and fireman in the locomotive, along with two conductors and a brakeman. Despite being a pure freight train EGz 6143 carried a passenger, Mister Zimmer, who rode in a package car towards the back of the train as he was escorting a dead relative’s remains to Berlin. Pulling the train on the day of the accident was a DR (Deutsche Reichsbahn, Germany’s national railway at the time) Series 17.
The Series 17 is a large steam locomotive introduced as the Prussian S10 in 1910 mainly for express passenger services. Each Series 17 measures 20.75m/68ft in length (including the pulled tender) at a weight of 77.2 metric tons and can reach a speed of 110kph/68mph. The locomotives have three driven and two leading axles, with the pulled tender having four axles of its own.
The accident
Around the time of the accident construction work was taking place at the Trogenbach-Viaduct, with the original rectangular truss-structures being replaced with “fishbelly-beam” type structures. Due to the construction-work the bridge only had one usable track, which was of temporary nature and had a 30kph/18.6mph speed limit.
On the 18th of February 1924 EGz 6143 is approaching the bridge from the south, making its way towards the mountains. Stopping in Lichtenfels station a brake-check is conducted, with some of the train cars only passing after several attempts. There is no record of any consequences for the suspicious behavior of the brakes, it appears that the train was released once all the brakes delivered passable results. As the train starts to climb the southern section of the rail line’s mountainous part the pressure gauge in the locomotive’s cab (allegedly) displays sufficient air-pressure for the braking-system, with no sign of a fault. The train eventually crests the highest point of its journey and begins the winding descend towards Ludwigsstadt. Passing through Steinbach am Wald 5.7km/3.53mi from the Trogenbach-Viaduct everything seems to be in order. In reality, the train was likely doomed at this point, with derailment being a matter of place rather than time.
As the descend grows steeper the driver and brakeman apply more and more brake-power, eventually completely draining the system of air-pressure, with little to no effect. Usually, dumping air pressure would mean a train’s brakes clamp down completely. Instead the train keeps picking up speed, eventually reaching the section just south of Ludwigsstadt which has a 25‰/2.5% descend. This means on 100m/328ft of track the train looses 2.5m/8.2ft of altitude. Here, the train was meant to have slowed down to 30kph/18.6mph. Instead estimates put the speed of the locomotive at the start of the bridge in the vicinity of 100kph/62mph. The locomotive derails to the right on a temporary set of points at the beginning of the bridge and goes flying off the bridge, pulling 21 of its train cars along with it. The driver is ejected from the locomotive on its way down before it crashes to the ground between two houses, followed by a hail of debris and train cars. By morbid coincidence much of the train comes down on the town’s graveyard.
The fireman is also ejected from the locomotive, he survives the fall and ends up beneath the roof of a freight car which protects him from further debris. The two conductors and the brakeman also survive. Mister Zimmer’s car remains on the bridge, but the jolting of the derailment causes a coal-oven to fall over, igniting chemicals aboard the train car which trigger a fatal explosion. Mister Zimmer is the second fatality of the accident.
Aftermath
The falling train severely damages several houses, but despite that nobody on the ground is injured in the derailment. Witnesses to the crash pull one of the conductors from a burning train car moments after the accident, his coworker and the brakeman survive after having jumped off the out of control train ahead of the derailment. Several fires are burning in the wreckage as responders and witnesses head to the site, both atop the bridge and on the ground where most of the train has ended up. The fireman is rushed to the nearest hospital, receiving treatment for life-threatening injuries he suffered as he fell from the bridge.
Most of the train cars burn up after the accident, leaving little to be examined aside from the locomotive’s remains. The statements by the survivors from the crew, especially the fireman, along with the conditions encountered on the day and the condition of the locomotive, which was without any sign of pre-existing defect, help the investigators in narrowing in on the most probable cause. At 65 years old the driver had had a lengthy career without incidents, and the fireman doesn’t recall any negligent behavior that could’ve led to the accident, such as excessive speeding.
Running out of alternative causes the investigation concludes that moisture had accumulated in the pneumatic lines and eventually froze solid due to the cold temperatures on the day of the accident, plugging the line in one or more places. Early stages of the clogging of the brake lines may have already caused the faulty behavior during the brake-check at Lichtenfels station, with the partially blocked pneumatic lines only eventually letting enough air pass through to operate the brakes. Once all the brakes were released and the train was travelling along the rail line the icy plugs formed again, completely cutting several train cars off from the pneumatic system. As the train started to descend towards Ludwigsstadt the driver applied the brakes, reducing air-pressure in the pneumatic system and thus starting to press the brake-pads onto the wheels. However, the ice in the pneumatic lines acted like a closed valve, keeping the lines beyond the plugged spot pressurized and the brakes released. With only part of the train’s brakes working gravity overcame the resistance of the brakes rather easily, causing the train to pick up more and more speed regardless of the driver’s inputs. There was nothing the driver could do to keep the accident from happening once his train entered the descending part of the rail line, the train was going to derail sooner or later. The construction-site at the bridge, which featured temporary track that was to be navigated at exceptionally slow speed, ended up being what did the train in, demanding too sudden a change of direction for the locomotive to obey.
After the accident the rail line remained closed for recovery and repairs for five days before limited traffic was allowed to cross the bridge, it’s unknown if the houses struck by the falling train were demolished or repaired. The DR introduced a mandatory brake-check for northbound trains at Steinbach am Wald, the last place where a faulty braking-system could be spotted ahead of the downhill section of the rail line.
The bridge was upgraded with concrete sleeves for the stone supports ahead of the line’s electrification in 1935, and narrowly escaped destruction at the end of WW2 when the town’s deputy mayor flatly refused orders to blow it up as an attempt to slow advancing allied forces.
The DR series 17 was retired by 1954, the only survivor of the original type is a cut-open unit in a Museum in Berlin used to explain how a steam locomotive works. A modified version (Series 17.1) has a single working survivor. People are no longer allowed to ride in freight cars for any reason, and trains have stopped using coal ovens for heating a long time ago, with most modern trains using electric heating.
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