Railway accidents may be classified by their effects, e.g.: head-on collisions, rear-end collisions, side collisions, derailments, fires, explosions, etc. They may alternatively be classified by cause, e.g.: driver and signalman error; mechanical failure of rolling stock, tracks and bridges; vandalism, sabotage and terrorism; level crossing misuse and trespassing; natural causes such as flooding and fog; hazards of dangerous goods carried; effectiveness of brakes; and adequacy of operating rules. The following is an incomplete chronological list of railway accidents and incidents in India.