Russell Hill Railroad Accident
The railway accident at Russell Hill (Russell Hill subway accident) was a rear-end collision on the Yonge-University line of the subway from Toronto (Toronto Subway) in Canada. On August 11, 1995, shortly after six o'clock in the evening, a driver crashed into a train standing in the tunnel under Russell Hill north of Dupont station . Three people were killed and 30 others were injured, some seriously. The causes were, on the one hand, human error and, on the other hand, a design error in a travel lock .
procedure
At that time, the Toronto subway operated without cab signaling based on optical signals. Simple route signals worked with a three-colored lamp - red means stop, yellow indicates a red at the next signal, and green means clear route. Before branching off, the signals have two lamps: The upper one shows the route clearance as usual, the lower signal is also red for stop and shows yellow for a branching position and green for the executing position. In the case of a normal passage at a distant signal, this can be yellow over green, whereby this is to be treated like a simple yellow signal.
In addition, there are signals with another white lamp, which serve to optimize the speed, the so-called “grade timing” (roughly “time segment process”). If a distant signal shows yellow and indicates a subsequent main signal with red, white can also be switched on to indicate that if the speed limits for this section are observed, the next signal will be on passage when the train reaches the signal. On longer downhill stretches or on winding stretches with poor visibility, the route is equipped with signals at short intervals. In normal driving mode, after a yellow over white, the next signal will be red over white, and when approaching it jumps from red over white to yellow over white and the driving lock is lowered. On the Toronto subway, the drivers have got used to exhausting the system's tolerances and approaching a red and white signal at the target speed - if you accidentally too fast after receiving a yellow and white signal, you will be braked by the travel lock.
The “grade timing” system is used throughout the section from St. Clair West station to Dupont station. The SP77 / X38 signal behind St. Clair station is a turnout signal that is regularly yellow over green over white - the next signal is red over white, but the route can be expected to be free. On the day of the railway accident, however, the signal was yellow over green, so that the following signal SP71 is red and an unconditional stop can be expected. The reason was that there was still a train in the following section.
Platoon leader Robert Jeffrey later testified that he remembered signal SP77 / X38 as yellow over white. This is impossible with this signal, but a reflection from one of the lamps may have been misinterpreted. In any case, he assumed that the “grade timing” was active and consequently drove towards the next signal without braking. Jeffrey does not remember the following signal settings. However, these can easily be derived from the function of the system.
At the following signal SP71, which was therefore red, the travel lock was not triggered due to a design error, so that the train passed through without braking. It was not possible to clarify why the driver ignored the signal to stop - possibly he assumed that it was red over white and the technically enabled passage is simply related to the fact that it jumped to yellow over white shortly beforehand. So he assumed an active “grade timing” for the following section of the route and was based on the usual route speed.
So the train drove on to the third signal SP65, which it had to assume would jump from stop to passage in the same way. This showed red - not red over white - and again Jeffrey disregarded the stop requirement. He did not apply the emergency brake until the stationary train came into view, which was waiting on the following signal SP53.
Each train was occupied by around 200 to 300 people. In the impact at 6:02 p.m. at around 50 km / h, 3 passengers were killed and 30 seriously injured were brought to hospitals. About 100 people later reported for compensation for minor injuries. After the accident, the route was closed for five days.
examination
In addition to the easily misunderstood signaling, the investigations also focused on the driving lock. As is common in North America, it is a T-shaped lever that is placed on the right-hand side beyond the power rail. When driving through it lies on the ground, when the associated light signal shows red, the lever is raised - in this position the head element will hit a switch on the first car, which will trigger the vehicle's emergency braking system. On the trains of the H5 series used in Toronto at that time , the release is located on the first axle frame, where the position above the track and the distance to the travel lock can best be secured.
In this case, a travel lock from Ericsson was used, which is actually intended for installation on the inside of the power rail, and which was modified via an extension piece so that it can be operated on the outside of the power rail. During the investigation, it was found that the construction, which was 18 years old at the time and in which the bearings of the travel lock have some play after a while, protruded a few millimeters into the clearance profile of the vehicle. Under normal circumstances, a vehicle will not fill its clearance profile - but if the rails and wheels are already a bit worn, and the signal is in a curve here, then the vehicle protrudes very far from the center.
In the case of the railway accident, this led to the front of the train bumping into the installed travel lock and thus pushing it down slightly. It then swung up again immediately, but not fast enough to still be able to press the trigger on the first axle frame. Ultimately, the construction of the travel locks on this route for train protection was ineffective.
In their report, the investigating authorities made 18 recommendations for improving safety regulations. Based on these recommendations, the Toronto Transit Commission created a 236-point checklist and then reviewed its implementation every year (including the replacement of all travel locks). In August 2009 there were only two issues left that concern a speed control system (this system was then in the implementation phase).
See also
Individual evidence
- ↑ Ten years after. Transit Toronto, August 6, 2005, accessed July 30, 2010 .
- ^ Due Diligence Checklist Russell Hill train accident. (PDF, 134 KB) Toronto Transit Commission, August 7, 2009, accessed July 30, 2010 .
Coordinates: 43 ° 40 ′ 56.5 " N , 79 ° 24 ′ 42.7" W.