B1/1998R Trains colliding at Suonenjoki, on August 12, 1998

On August 12, 1998, Wednesday morning, a train incident, occurred at Suonenjoki. An InterCity passenger train and a freight train collided. The IC72 passenger train was travelling from Iisalmi towards Pieksämäki with the intention of continuing further to Helsinki. The freight train was travelling from Kouvola to Iisalmi. The trains collided on a curve in the southern part of the railway yard when the passenger train had proceeded about one minute after leaving Suonenjoki station passenger platform. The drivers of both locomotives activated the emergency brake immediately upon catching sight of the front of the approaching locomotive. When starting the emergency braking the speed of the passenger train was 70 km/h and at the moment of the collision, it was 44 km/h; the corresponding speeds of the freight train were 27 and 25 km/h. As a result of the high speed of the passenger train and the heavy weight of the freight train, the collision was very violent. The entire passenger train retracted by 4 metres and the rear end of the locomotive of the freight train rose high up in the air while two cars pushed thereunder. Nevertheless both trains remained on the railway bed and mostly on the track.

In addition to the locomotive, the passenger train consisted of five day coaches and one restaurant-car. Beside the engine driver, two conductors and two train hostesses, there were 46 passengers on board the train, 26 of whom were injured, one person seriously. The freight train consisted of one locomotive and 41 wagons.

The driver’s cabins of the Sr1 electric locomotives of both trains, the bogies and the underframes were badly damaged. The first two wagons in the freight train were wrecked and the rear ends of all six passenger cars buckled. The frame structures of the entrances in the passenger train yielded as they were designed to do.

The Suonenjoki train accident was a result of the driver of the passenger train starting to accelerate the train upon leaving Suonenjoki station without considering the red "stop" aspect (prohibiting proceeding) in the main signal in the departure direction.

The alertness of the driver had enervated as a result of numerous factors. The most important factor is that the driver of the IC train started off as based on an incorrect repeater display .Two reliable eye witnesses told that they had seen the repeater repeating the aspect of the main signal in the departure direction, flashing a green light at the arrival of the IC train at the station. The flashing of the repeater indicates that the main signal in the departure direction ought to display a "proceed" aspect. The Investigation Commission nevertheless concluded that the main signal in the departure direction displayed a "stop" signal. The investigations conducted revealed a defect in the connection of the repeater, which as a result of two simultaneous relay defects enabled the flashing of the repeater in spite of the "stop" aspect in the main signal.

The driver regularly receives "signals" which jointly lead to a promptly timed departure. The very punctual InterCity trains operate in almost identic modes when arriving at or departing from stations, particularly on low-density sections of line. Generally the IC trains are ensured priority of route securing whereas other trains are controlled to take a siding and wait. In most cases already when the train arrives at a station, the signals display an aspect permitting proceeding and thus the departure of the train may be operated immediately upon all new passengers having entered the train if the timetable permits the departure. In this case the driver did not expect the main signal possibly displaying a red "stop" aspect prohibiting proceeding, but he gathered the conductor’s "ready for departure" bell signal and the exact time as sufficient indicators permitting departure.

Also an excessive concentration on the exact departure time by the second attracted the driver’s attention at the expense of the signals. Among many IC drivers a meticulous preciseness in following the timetable has become somewhat of an "obsession" which may cause the driver to ignore the other important aspects in running a train.

A further factor which most probably contributed to the accident was the very bright daylight rendering it difficult to distinguish between the different signal aspects and weakening the stimulus of the red "stop" aspect.

The Investigation Commission recommends measures for improved train safety. The recommendations suggest an acceleration of the construction of the automatic train control (ATC) by a planning and design of a lighter local ATC system. The Commission furthermore suggests a recording of the train track and signal displays, a more efficient recording of the remote-control signalling device operations, a removal of the main signal repeaters, a more efficient control of the checking and acceptance procedure in signalling device planning, and finally a development of the brakes in fast passenger trains.

B1/1998R Report (pdf, 1.05 Mt)

• Recommendation S93
• Recommendation S94
• Recommendation S95
• Recommendation S96
• Recommendation S97
• Recommendation S98