Train trip is not always safe. A derailment occurs when a vehicle such as a train runs off its rails. This does not necessarily mean that it leaves its track. Although many derailments are minor, all result in temporary disruption of the proper operation of the railway system, and they are potentially seriously hazardous to human health and safety. Usually, the derailment of a train can be caused by a collision with another object, an operational error, the mechanical failure of tracks, such as broken rails, or the mechanical failure of the wheels. In emergency situations, deliberate derailment with derails or catch points is sometimes used to prevent a more serious accident.
History......
Railroad wrecks in the 19th century were sensational, and the newspapers claimed them to be due to human failure or the consequence of corporate greed. It took railroads several decades to improve train-control practices and adopt safety devices sufficient to make railroad travel truly safe. Very few passengers were killed in train wrecks in the US before 1853. The early trains ran slowly and made short trips, night travel was rare, and there were not many of them in operation. While trains were convenient for travel and for transporting goods, they had become a greater danger over the years as their speed had increased. While fatal railway accidents occurred about once a year previously, there was a sudden 800 percent increase in accidents in 1853. Some railroad accidents were caused by human error, but other causes included derailment, explosions on board, equipment failures, and bridge collapses. Thereafter, the rate of accidents returned to its former level.
Boiler explosions had been noted in locomotive-type fire tube boilers when the top of the firebox (called the crown sheet) failed. This had to be covered with a significant layer of water at all times or the heat of the fire would weaken it to the point of failure, even at normal working pressures. Low water levels in the boiler when traversing a significant grade could expose parts of the crown sheet. Even a well-maintained firebox could fail explosively if the water level in the boiler was allowed to fall far enough to leave the top plate of the firebox uncovered. Due to the constant expansion and contraction of the firebox a form of "stress corrosion" could also take place at the ends of the firebox plates. This corrosion was accelerated by poor water quality and the build-up of boiler scale. A fuel explosion within the confines of the firebox (actually the ignition of unburned gases caused by an inappropriate air/fuel mixture) could also damage the pressurized boiler tubes and interior shell, potentially triggering a structural failure. The majority of locomotive explosions were found to be related to these circumstances, and constant attention to the engine was found to be the best defense against catastrophe.
On 6 January 1853, the Boston & Maine express, traveling from Boston to Lawrence, MA, derailed at forty miles an hour when an axle broke, and the single coach went down an embankment breaking in two. Only one person was killed, the eleven-year-old son of President-elect Franklin Pierce, who was also on board but was only badly bruised. A few days later, on 23 January 1853, at Glen Rock, PA, the conductor B.A. Stells was lost after the caboose was detached from its train cars in a forest during a blizzard. The body of the man and the car were not found until Spring. On 6 May 1853, a New Haven Railroad train ran through an open drawbridge at Norwalk, CT and plunged into the Norwalk River. Forty-six passengers were crushed to death or drowned. This was the first major railroad drawbridge accident.
On 17 July 1856, at Fort Washington, PA, there was one of the most infamous train wrecks to ever occur in the US and the deadliest in the world up to that time. Known as the Great Train Wreck, two North Pennsylvania Railroad trains, one of them carrying 1,500 Sunday School children to a picnic, collided. Upon impact, the boiler of the passenger train exploded and the train carrying the children derailed. Fifty-nine people were instantly killed, and dozens more died from their injuries. The conductor of the passenger train committed suicide the same day, although he was later absolved of any responsibility.
Finally in this sampling, on 11 May 1858, at Utica, NY, two New York Central trains, a westbound freight and the eastbound Cincinnati Express, passed on parallel tracks on a forty-foot wooden trestle over Sauquoit Creek. It collapsed under their combined weight, utterly destroying the passenger train, killing nine and injuring 55 persons.[1]
During the 19th century derailments were commonplace, but progressively improved safety measures have resulted in a stable lower level of such incidents. In the US, derailments have dropped dramatically since 1980 from over 3,000 annually (1980) to 1,000 or so in 1986, to about 500 in 2010.
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