Train Fires:
Fire Hazards of passenger Rail Vehicle Interiors

Railways is the principal mode of transportation in India and lifeline of the nation as it is affordable for the common man. It is the only viable means of man and material over long distances in our vast nation. Consequently, any accident in Indian railways is matter of public concern especially in case of fire where large scale deaths result due to asphyxiation & burning. The result is heavy toll of human lives & colossal damage to property.

In the event of fire on a moving train, evacuation is not possible. Even if the train is stationary, trains passing on adjacent tracks make evacuation dangerous. Besides passenger might not get sufficient time to leave the compartment in the first few crucial minutes of fire as escape is hindered by panicky rush, poor visibility due to smoke, fixed windows and closed doors which may even get jammed. Even if only a part of train catches fire, movement to a place of safety to other parts of the train cannot be ensured as fire rapidly rages out of control due to the presence of highly combustible materials which are a part of the berths & seats in a coach.

Fire in trains generally occur due to some inflammable material being carried in the train by passengers which can be ignited by a small spark, cigarettes, matchsticks or cigarette lighters. Materials used in coach making are highly combustible and catch fire very quickly. With the increasing use of polymeric/foam plastic materials, the hazard of smoke/combustion toxicity is also increasing day by day. New materials with different chemicals are being introduced in the market. The use of these material can not be stopped because these materials have advantage over traditional materials but some restrictions can be definitely imposed. The advantage of synthetic foam become immediately obvious. It provides more choices with greater range of properties as lighter weight, inherent colourability, aesthetic, ease of fabrication and lower cost.

Latex foam and Polyurethane foam are generally used as cushioning material. Now, new materials like polyester Blocks, nylon fibre sheets are emerging as new materials for seat cushions. Cushioning material, is an integral component of a compartment, specially in sleeper coaches. These foams are highly flammable & catches fire quickly engulfing entire vehicle within few minutes. Once on fire, it consumes oxygen at a very high rate and generates a lot of heat & smoke along with toxic gases. Carbon monoxide (CO) is main toxic gas generates in all fires due incomplete combustion. Very little amount of CO may be the cause of death as it has 200 times more affinity for haemoglobin than Oxygen thus causing decreased oxygen carrying capacity and hence hypoxia. Besides CO many toxic gases like hydrogen cyanide, iso-cyanates, oxides of nitrogen etc. are also produced. Polyester blocks have another serious fire hazard of burning droplets. A small spark becomes the source of ignition of foamed block. As the temperature rises the material first melts and then the flame is set and reaches to flash point. If burning droplets drop to the floor, it will ignite other flammable material present in the coach including luggage, berths partitions, panels, and the vinyl flooring. The burning droplets of the polyester blocks are very dangerous when the passengers are asleep. Curtains rapidly catch fire and flame spreads vertically very fast setting the other materials on fire too.

Considering the above facts, preventive fire safety is an important aspect for saving human life and property. When a vehicle is subject to an engineering change involving the replacement/ substitution of material, or the introduction of new or revised systems/components, the fire performance of the vehicle should not be degraded and the relevant standards should be strictly followed.

To confer protection against fire and reduce the fire hazards of polymeric foam materials, many innovative methods are available. Fire blocking systems can reduce the flammability of the bodies of organic materials that thermally decompose to give flammable gases. The system not only reduces the flammable gases but also traps the burning droplets. A number of fire retardant compositions comprising the product of reaction of a foamable composition and certain inorganic filler materials including microexplodable micron-sized particles, expandable alkali compounds and ammonium salts of a phosphate also serve the same purpose.

Recently, Railways has announced to put cushions on wooden seats in unreserved coaches in an effort to provide more facilities to passengers. In keeping these efforts, all necessary steps should be taken to ensure safety and prevention of fire hazards. With so much technology available, a neglect of safety against fire would amount to the betrayal of millions of passengers who have faith in railways.

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