Tram accident

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Picture 1. A tram running on tracks isolated from vehicle lanes in Helsinki, Finland

A tram accident is generally an accident in which a tram is involved (see a tram in picture 1). When general traffic safety is evaluated, as in traffic accident statistics, any accident involving a tram or a tram system can be considered to be a tram accident. Some statistics concerned with public safety collect information on any incident in a tram or a tram system.

[edit] General

Tram traffic is typically considered as environmentally friendly, efficient, comparatively safe^[1] and, after investments, is a relatively cheap way to transport passengers in cities. A tram typically travels with a relatively slow speed in cities, however, light rail vehicles may drive with a speed of 70 – 100 kilometres per hour (approx. 44 - 60 miles per hour).

[edit] Accident types

However, accidents do happen, and some accidents seem to be serious for light traffic. In tram accidents, a person may be hit by a tram, a tram can collide with another vehicle, or drive over a person. A tram can derail after a collision, in case of broken track, if any object on the rail lifts the wheel from the track, in case of junction failure, or if a tram drives with a far too high speed into a junction or curve. In some cases, a tram may even overturn.

Picture 2. Tram driver's safety against violence can be ensured with a good cabin and surveillance cameras.

A person may also fall from a tram or, despite safety systems, get jammed between the doors. Persons also fall on the rails while crossing them. Sometimes persons lose control of their vehicle (like a bike) when the wheels run along with the tramway tracks ^[2]. In some cultures people travel also outside the crowded trams, and are in danger of falling or being trapped between tram cars, or between a tram and any obstacle and vehicle on the road. People may also travel outside the trams for fun, for excitement, or under influence of intoxicants.

A person can also climb over a tram car, or in other ways get in the contact with the electric conductors or other electric appliances of a tram, and get an electric shock. Occasionally, when a tram is braking rapidly or collides, people may fall in a tram or hit other persons or tram structures. In traffic safety statistics, accidents at tram stops and in the vicinity are sometimes evaluated. In these accidents, passengers e.g. get hit by a car while coming out of a tram or crossing the street to the tram stop. Even suicides, non-movement fatalities like falling from a bridge to electric lines, fires at stations, and "bridge strikes" (a vehicle hits railway bridge structures) can be marked in railway accident statistics^[3]. Vandalism may cause damage to tracks, trams, and even lead to derailment of a tram. Violence in trams and at tram stops can be a concern when people estimate the safety of trams. Also the tram driver should be protected against violence and robberies (see a driver's cabin in picture 2).

Picture 3. Emergency brake and emergency hammer near a tram door.

[edit] Analysis of tram accidents and consequences in the literature

Very limited information on tram accidents exists in scientific literature.

In Sheffield, UK, cyclists appear to be the group at highest risk to be injured in tram accidents, followed by pedestrians and motor vehicle users ^[4]. In Sheffield, less than one third of casualties had a fracture, and approximately every tenth injured person had a hospital admission. In Gothenburg, a majority of 60 % of fatally injured persons were under the incluence of alcohol ^[5]. In Gothenburg, the incidence of non-fatal injuries was 3 per million tramcar-kilometres, and the mortality was 0.2 per million tramcar kilometres. The most fatal tram accident in Gothenburg happened when a high-speed runaway tram hit dozens of pedestrians and several vehicles. The accident happened after a technician manually released the brakes automatically activated after a power failure.

The mortality of pedestrians hit by a tram seems to be much higher than the mortality of pedestrians hit by a motor vehicle. Typically the most seriously injured persons have been caught under or between tramcars ^[6]. Non-impact absorbing parts at the side of the trams may lead to serious head injuries even at low speeds ^[7].

Picture 4. A protective shield in front of a tram. When a person hits the detector (yellow arrow), a shield (red arrow) launched avoids the person getting under the wheels.

In Austria, accidents of children at bus or tram stops were analyzed within a 6-year period. 6 children were injured by trams. Accidents happened while crossing the track, a child ran against a tram, a child was crossing at a crosswalk or looked at wrong traffic lights. Most of the children hit the side of the tram. In addition, 4 children were injured by a car at a tram stop.^[8]

Despite the fact that safety measures should be taken to avoid any tram accidents, these accidents are not nearly the most typical injuries. For example, in Victoria, Australia, injuries among adults 65 years and over were investigated. While falls (3382 cases) were mentioned as the major feature of injury, two adults were hit by a car when crossing a road to a tram^[9]. In Department of Forensic Medicine in Bydgoszcz, Poland, 81 autopsies were performed on persons who died in accidents involving rail-vehicles in 1992-2002. 20 % of the victims died in tram accidents, and 80 % died in train accidents. The most common reason for death was a multiorgan failure. In tram accidents, 86 % of victims were male. The victims of tram accidents did not suffer injuries of the highest severity like amputations.

In addition, some national authorities keep statistics on tramway incidents^[10].

Picture 5. Unburnable, round shaped, flexible and/or impact absorbing materials are used in the tram interiors.

An example on an authority collecting accident and incident reports from national authorities is the European Railway Agency. The Agency has a public safety database on railway licences, certificates, safety indicators, national safety rules, and accident investigations^[11]. In the European Union, the safety of railways has been regulated with directives, which also require e.g. the collection of common safety indicator statistics from the member countries. In the EU, common safety methods (CSMs) and common safety targets (CSTs) have been set for European railways.

[edit] Safety measures

Injury-reducing measures in the vehicle design and in the traffic area, especially at and near tram stops, might reduce the injuries caused by trams^[12]. When evaluating general traffic safety, the safety of tram lines, train and tram crossings are mentioned to be an area deserving special attention^[13].

Picture 6. Some safety measures in a tram door.

The trams, tracks, and the environment of a tram systems should be physically planned as safely as possible. Even physical structures should be safe and minimize damage in case of accidents. Various kind of stress factors and forces should be calculated and assessed to create a tram system with diminished possibility of structural failures, derailments etc. In case a tram rides in a tunnel or on a bridge, various fire, derailment, and entrapment safety measures should be thought about. The trams may contain emergency brakes. Protective shields in the front of the tram, "catching" people, avoid them getting underneath the tram (see an emergency hammer in picture 3 and a catcher in picture 4). Trams should be designed to have impact absorbing materials in front and side constructions. Lifting points can be marked for fire brigades to help rescuers to find safe and strong enough parts of the tram when e.g. lifting a tram to rescue a patient underneath it. Inside the tram the structures should also contain impact absorbing materials and round shapes instead of sharp edges (see interior material in picture 5). Automatic door controlling sensors decrease the possibility of entrapment injuries (see a tram door in picture 6). Handrails may prevent people falling in acceleration, curves and braking. Especially elderly people need seats and time to find one and sit before the tram moves. Trams can contain fire safe materials like low smoke and halogen-free cables, driver's vigilance control systems, and programmable logic speed controllers^[14].

Picture 7. Some details on safety planning of a tram stop.

The fire brigades may carry special tools for tram accidents, like heavy extrication tools, grounding equipment, and hydraulic lifting jacks for trams. Some trams are able to drop some sand on the rails to increase the friction during emergency braking. Interestingly, the most slippery season for trams is not necessarily an icy winter, but seasons when leaves fall from trees. A brush car can be used to clear the rails^[15].

A quality system may guide the safety of a tram system. A tram system may have a control centre following the trams, having radio contact with the drivers, and ability to contact and guide guards, emergency dispatch centre, or repair patrols. A tram typically carries first aid kit, a radio and/or a phone, some tools, and a fire extinguisher. Basic first aid, prodromic driving manners, safety courses, and protocols to follow in an accident are taught to tram drivers.

Various cities and traffic companies have given safety and traffic instructions for passengers, pedestrian, wheelchair users, cyclists, and motorists ^[16][17][18]. These instructions tell how to behave in traffic to avoid accidents. For example, the instructions advise not to obstruct the tramway, suggest motorists avoid driving directly on the track, and tell the pedestrians to use designated crossways and to look both ways before crossing the tracks.

Picture 8. Safety measures when a tramway track merges with a vehicle lane.

Some cities or areas have systemically developed new safety systems and planned new, safer tram stops even in new locations (see a tram stop in picture 7). These measures have included e.g. accessible tram stops, safety staff, road-based improvements like speed humps near tram stops, better lighting of tram stops, raised dividing strips to separate trams and motorists, traffic light sequence changes, and electronic flashing “give way to trams” signs to warn other traffic in places where necessary (see warning signs in picture 8) ^{[19][20][21][22]}.

Local tram regulations may give requirements for the passengers e.g. not to carry flammable, soiling or destructive chemicals or too space-blocking packages in trams^[23]. Enlightenment of children and adults can be done also by using games and test ^[24].

Naturally the state of traffic legislation, traffic culture, and safety culture in the tram and traffic system may have an influence on tram accidents. Tram stops can be separated with barriers from the street ^[25]. Speed limits can be used near the tram stops, and strips painted between tram tracks^[26]. Tram lanes can be also separated from other traffic. Trams may have their own traffic lights, which are integrated to work with normal traffic lights and stop the traffic when a tram stops at a tram stop. In some areas the junctions are warmed during winter to avoid ice and snow disturbing the functioning of the junction (see a warmed junction in picture 9).

Picture 9. A warmed tramway junction.

Tracks, junctions, trams, tram traffic lights etc. should be regularly inspected and maintained.

[edit] Rescue tactics

In a tram accident, the first mission is to prevent further accidents, and additional damage and injuries (see an accident scene in gallery picture 1). A ground connection is used to prevent electric shocks from overhead lines (see an emergency ground connection in gallery picture 2). The accident scene is isolated, and police or fire brigade controls the traffic.

The accident scene is surveyed, and in the case of several injured persons, a triage process or other recognition of patients’ states is done. The most critically injured patients get more, faster, and better quality attention and treatment. In the case of a patient underneath a tram, lifting bags or hydraulic jacks brought by fire brigades can be used to elevate the tram and release the patient (see lifting points in picture 10) and a tow car lifting a tram in gallery picture 3). A crane can be used to lift a tram, too, or an overturned tram. If a patient is trapped inside crushed structures, various kinds of extrication tools, like hydraulic spreaders, rams, cutters, and circular saws can be used. In some cases, it is also possible to drive the tram backwards, but in most cases this would only cause more injuries to the victim.

Picture 10. Lifting points marked near the bogie of a tram (red arrows). Notice the yellow light increasing the visibility of the tram on its sides.

While cutting, lifting or turning an overturned tram or vehicle, structures often have to be stabilized to avoid the movement of the vehicle, to prevent the risk of movements of suspension, and to avoid falling of lifted vehicles on the patient or the members of the rescue crew ^[27]. Cranes, tow trucks, hydraulic jacks and rollers can be used to move a derailed tram back to its rails (see a roller and winching in gallery picture 4 and gallery picture 5).

After the patients have been treated and transported, a police investigation on the scene continues. The victims and witnesses can be interviewed on the scene, or later. After investigation the vehicles which collided are allowed to be moved from the scene. In severe accidents, special traffic or accident investigation boards may analyze the accident and its consequences, and give recommendations to improve safety in traffic. After the accident, the accident scene shoulde be cleaned. The tram, the tracks and the overhead lines may need repair (see gallery picture 6, gallery picture 7, and gallery picture 8).

[edit] Picture gallery: a tram accident scene - collision of a tram and two buses

Gallery picture 1. A general view. A triage has been done and injured patients treated and transported.	Gallery picture 2. An emergency ground connection.	Gallery picture 3. A heavy tow truck lifting the head of a tram.	Gallery picture 4. A derailed bogie is lifted with hydraulic bags, and a roller is used to move the tram onto its rail again.
Gallery picture 5. A rescue unit is winching a derailed tram back to its rail.	Gallery picture 6. A repair truck with an aerial work platform checks and repairs the pantographs and overhead lines.	Gallery picture 7. A sweeping machine is used to collect litter and leaked fluids on the street.	Gallery picture 8. In this accident, the tram derailed when a bus hit it (see the marks on the asphalt). The tracks remained intact and needed no reparation.

[edit] See also

• Tram
• Tram controls
• Tramway track
• Tram stop

[edit] References