How could have the Bhopal disaster been prevented?

How many people died in the tangiwai disaster and could it have been prevented?

• Answer:

  151 people died in the Tangiwai disaster, of which only 131 were found - the remaining twenty were presumed swept away by the Whangaehu River to the Tasman Sea. The dead consisted of the driver and fireman, 148 second-class passengers, and one first class passenger. The crash was hard to prevent. In 1953, the central North Island Main Trunk still used tablet signalling with semaphore signals, and there were no track circuits. The driver and firemen had been flagged down by a passing motorist, and evidence found that the train had applied its brakes at least 700 metres before the bridge. The train was 11 carriages long, plus locomotive, so it would have been hard to stop. Today, warning systems have been installed to prevent this type of disaster occuring. Track circuits can detect broken tracks and stop trains. In addtion, a flood detection device is placed upstream of the bridge, which gives 90 minutes warning of a flood or lahar before it reaches the bridge. The warning is sent to the national train control centre in Wellington where they can stop trains.