It was the worst ever accident for the Rajdhani Express — a train supposed to be the best maintained in the railway fleet. And it happened in Mughalsarai division, the busiest in the country, earning the maximum revenue for railways. Though Railway Minister Nitish Kumar and other senior officials were quick to cry ‘‘sabotage,’’ sources said they were jumping the gun and a clearer picture would emerge after an inquiry. There were other factors that could have contributed to the accident. The girder bridge was built in 1916 and required maintenance. The bridge was badly damaged as its pier broke due to the impact. The fish-plates — removal of which is being claimed to be the cause of the accident — were to be physically opened every three months to ensure they had not been sheared due to heavy traffic.