Careening Crocodile: The 1948 Wädenswil (Switzerland) Runaway Train Derailment

Wädenswil is a city and municipality of 24832 people (as of 2020) in northern Switzerland, located in the canton of Zürich 13km/8mi northeast of Zug and 20km/12.5mi south-southeast of the city of Zürch.

The location of Wädenswil in Europe.

Wädenswil lies on the Wädenswil-Einsideln rail line, a largely single-track electrified main line opening in 1877. Originally intended to use a cogwheel-system on the steepest section this plan was scrapped after a fatal derailment during testing, leaving the line as one of the steepest regular gauge adhesion railways (regular wheels on regular rails with no other aids) at an incline of as much as 50‰/5% just south of Wädenswil. The line is owned by the Schweizer Südostbahn (SOB, Swiss South-Eastern Railway) since 1890 and is used almost exclusively for passenger services.

The approximate site of the accident seen from above today. The train approached from the bottom of the image (south). Note that the layout of buildings and roads changed since the accident.

In winter 1947/1948 the SOB and SBB (Swiss national railway) cooperated on “Ski trains” set up to take people from Zürich into the mountains in the morning for a day of skiing before returning in the late afternoon. On the day of the accident the train from Sattel back to Zürich consisted of an SBB Ce 6/8 II (numbered 14269) and nine older model two- and three-axle SBB passenger cars. The locomotive and cars were provided by the SBB along with a driver, while the SOB sent their manager of operations to act as a guide for the section of the route on SOB-tracks. The SBB Ce 6/8 II is a heavy electric locomotive designed to pull freight trains on steep gradients, mainly the Gotthard mountain railway, introduced in 1919. Each Ce 6/8 II measures 19.4m/64ft in length at a weight of 128 metric tons. The locomotive’s can reach 65kph/40mph, enough for alpine freight services. The Ce 6/8 II’s eight axles are set up in sets of 4 under the smaller articulated “noses” on either side of the central driver’s cab and transformer-compartment, with the inner three axles of each set being driven via coupling rods. This design coined the nickname “Crocodile”, which has since been adopted for various locomotives of a similar design. On the day of the accident the locomotive had likely been chosen simply by availability for the irregular service, and was pulling a train with 349 passengers who had used a great snow-situation to spend the Sunday skiing. According to a local source the train measured 149m/489ft in length.

A brand new “Crocodile” being delivered in 1921

On the 22nd of February 1948 the evening return-trip for skiers departed Sattel station at 4:49pm. Passing Samstagern station the driver intended to start slowing the train down, but found that the locomotive didn’t respond to his input. Witnesses later stated hearing a weirdly loud braking-noise for a train proceeding along at speed, which came from the driver activating the pneumatic brakes in addition to continuing to try and slow the train by reversing the motors (turning them into generators, increasing drag on the axles instead of driving them). The two men aboard the locomotive suspected a mechanical failure preventing them from using the motors to slow the train, and with the motors continuing to run at consistent power the pneumatic brakes alone failed to overpower the motors, which were meant to pull heavy freight trains up steep hills. The Ce 6/8 II puts out a continuous power of 1000kW/1340hp, which can be temporarily boosted as high as 1650kW/2240hp.

The train sped through the pre-, entrance, main- and exit-signal of Burghalden station without slowing down. The driver gestured to the station manager on the platform as the train went past, which was correctly interpreted as telling him to alert Wädenswil to, as far as the driver knew, an incoming train without sufficient brakes. Wädenswil station had two platform-tracks at the time as well as a dead-end siding serving the local cooperative of fruit- and wine-farmers (OWG). The signal box at the station was set up to so the entry-points were set to the dead-end siding unless the station had a free track available. As the ski-train entered the steepest section of the route both platform-tracks at Wädenswil were occupied, though, track 1 with a railbus and two passenger-cars which passengers were disembarking from and track 2 with the Chur-Zürich-express, a crowded intercity train that had just pulled into the station. The dispatcher at the signal box called the conductor at the platform and ordered him to have one of the two trains leave the station immediately. However, by the time the conductor understood the order both men knew that there was no time to do so, as the train could now be heard approaching, continuously using the whistle to warn people in the vicinity.

The signal box crew accepted that they had to send the speeding train into the dead-end siding, with an overrun of the buffer stop being the least severe outcome. A conductor aboard the train senses the imminent disaster and instructs passengers to brace for an accident, advising those with glasses to take them off. Meanwhile the SOB’s manager of operations has climbed along the side of the locomotive, intending to reach the first car to manually apply the brakes.

At 5:30pm the ski-train enters the dead siding and proceeds to crash through the buffer stop at its end. The locomotive tears away most of the trackside wall of a three-story building beyond the buffer stop, which houses flats and the OWG’s administration. Half the house proceeds to collapse onto the locomotive as it becomes stuck in the debris, creating an immovable barrier for the following train cars. The leading 4 cars are compressed into one another as well as into the back of the locomotive, which creates enough of a cushioning-effect for the rear five cars to remain on track with minor damage. Once the dust settles the train has been shortened to approximately 120m/394ft. 22 people are killed in the accident, among them the SOB’s manager of operations who is crushed between the locomotive and the leading car. At least another 32 are injured.

Both civilian and professional responders are on site immediately, having heard the loud crash and seen the cloud of dust rising into the sky as the train crashed into the house. Within 10 minutes all available responders are involved in the rescue-effort and, as the telephone-network breaks down, additional help is called in via the rail line’s radio. The sight of the wreckage reminds many of the recently-ended second World War, the look of the torn-open home with furniture and piping hanging off the edge being likened to the aftermath of a bombing.

Most deaths occur in the leading two cars, which ran into one another losing about 1/4 of their combined length. Civilians and firefighters create openings in the twisted metal by using any tool they can find, trying to gain enough access to trapped survivors for doctors to medicate them until they can be freed. 20 reservists from the Swiss Army who had arrived at the station with the prior train try to keep curious onlookers out of the way until enough police officers arrive to take over crowd control. Identifying the dead and severely wounded proves difficult, as most passengers didn’t carry IDs and those who did mostly had them in jackets which were stored in an onboard wardrobe. All survivors are rescued from the wreckage by 8:00pm, it takes another 18 hours to recover and identify all victims.

Responders and civilians work on rescuing survivors from the destroyed train.

With all passengers removed from the train the work to recover the wreckage starts, with most train cars being towed back off the siding. Examination of the locomotive shows the forces of the subsequent collisions, with the heavy machine having broken into three pieces, it’s “noses” barely hanging onto the main section with the cab. However, the fact that the noses acted as crumple-zones, leaving the cab largely intact, is what allowed the driver to survive the collision. Workers remove the debris of the house from around and above the locomotive before cranes are brought in to lift it up and clean up the debris underneath along with the remains of the buffer stop. As workers set the locomotive back down they discover that the whole thing is bent upwards, with none of the wheels being quite on the same level anymore. Lifting the locomotive again the SBB’s recovery-crew removes the damaged axles, leaving 2–4 axles according to different claims. With the coupling rods adapted to the new situation the locomotive is placed back on the tracks and actually leaves the site of the accident under its own power the week after the accident, crawling to a nearby maintenance depot at walking pace. There, investigators further examine the locomotive after previously discovering that the brakes, all of them, were in perfect working order.

The locomotive sitting in the debris of the collapsed house after the train cars were removed.

With a technical failure out of the question and the driver insisting that he kept trying to increase braking-power the investigation starts to focus on the driver’s controls in the cab of the locomotive. The Ce 6/8 II was equipped with a regenerative braking-system, which saw the motors acting as generators and using the motion of the wheels to create electricity which was then fed back into the catenary. If the driver intended to use this option he would turn the throttle-control (the “steering wheel” found in many older electric locomotives) down to zero before using the directional control switch to change the setting of the motors from “Forwards” (V) to “Forwards, deceleration” (BV). With the changed setting input on the throttle would now control how much electricity was demanded off the motors, rather than how much they were fed, which increasingly slowed the train.

A Ce 6/8 II’s control desk. The throttle-control is on the right, with the directional control next to it in the center. In the photo it’s set to “V” for driving forwards.

The conclusion reached by the investigation was a simple one: The driver had forgotten about and/or misread the directional control switch, leaving it in V when he intended for it to be in BV. As such, whenever he tried to increase braking-power he actually told the locomotive to go faster, feeding more and more electricity to the motors. In trying to slow what he thought was a runaway train he made it run faster until it reached its maximum speed even with the pneumatic brakes fully applied. The theory was proven when Oerlikon, the manufacturer of the locomotive, took investigators on an experimental re-enactment of the train’s journey, this time with the proper control-settings. The result was that the train descended the steep incline at 10kph/6.2mph, just as intended. Another experiment had the train enter the incline at 4x the intended speed and still stop safely. Since the driver knew about the speed limits the sole blame for the accident was placed on his incorrect control-input.

Coffins of the victims lined up and decorated for the memorial service a few days after the accident.

The driver was put on trial for a variety of charges in May 1950, with the public prosecutor’s office demanding a year in jail. Based on the prior experiments it was claimed that the driver knew something was wrong by the time he entered the steep decline, at which point an emergency stop could have safely brought the train to a halt. Passing Samstagern the train had reached 58kph/36mph, putting it past the point where a standard emergency brake application could have stopped it. It was here that the driver actually attempted an emergency stop. However, in the process of trying to stop the train he also moved the throttle-wheel to position 17 (out of 23), assuming this would create a high demand of energy from the motors. Instead, it had the same effect as pressing the gas pedal down in a car. Furthermore, calculations showed that excessive heat was now reducing the effectiveness of the pneumatic brakes. Why the driver never dropped the pantograph (cutting the power-supply to the locomotive) or stepped off the dead man’s switch is unknown. Instead he spent the remainder of the doomed train’s journey simultaneously throttling and braking the locomotive.

Only once the train had crashed did the driver discover the setting of the directional control switch. He proceeded to try and cover up his error by attempting to move it to BV, but damage to the control table kept him from moving the handle in any way. On the fifth of May 1950 the driver was sentenced to ten months of jailtime, set out to probation over 4 years, and to payment of the cost of the trial. The final sentencing lists charges of negligent interference with rail traffic, negligent manslaughter and negligent cause of bodily harm.

The house the train had crashed into was demolished after the accident, the already struggling OWG (dealt another blow by the accident) fought through several harsh phases until eventually ceasing operation in 2001, failing to maintain a sufficient market-share. It can be said that the company never recovered from the train crash as it never met pre-accident highs. A few years after the OWG was dissolved the last of its buildings were demolished, making way for a combined commercial and apartment building standing at the site of the accident today. There is no memorial of any sort, but the accident is far from forgotten by locals.

The site of the accident today, the train ended up (approx.) halfway down the front of the building.

The Ce 6/8 II remained in service with the SBB until the mid-1980s, being largely driven out of the mountainous routes by the 50s and losing their last assignments in shunting by 1986. Eight units remain to this day, most of which not in an operational condition. The various “crocodiles” remain a favorite with railway enthusiasts due to their odd design and are commonly found in model railway collections.

SBB Ce 6/8 II number 14305 pulling a historic passenger train in December 2021.


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