While the exact cause of the Kanpur accident will be ascertained after the inquiry report, prima facie it indicates towards rail fracture, the sources said.
Casualties also increased due to absence of modern Linke Holfmann Bush (LHB) coaches in the train, the sources added. Had there been stainless steel LHB coaches, then the damage could have been less as these coaches have more in-built safety features which can absorb shock and impact of derailment more effectively and as a result do not topple, they said.
The accident comes at a time when railways are undertaking a massive brainstorming exercise to generate new innovative ideas to improve rail functioning and making the train journey a pleasant experience.
Fourteen coaches of Indore-Patna Express derailed near Pukhrayan in Kanpur claiming 96 lives so far.
This is the second derailment in two days as the four coaches of the Bhatinda-Jodhpur passenger train derailed yesterday at about 2 AM leaving a dozen passengers injured in Rajasthan's Sriganganagar district.
Railway Minister Suresh Prabhu, who has rushed to the site to monitor the situation at ground zero, ordered an inquiry into the accident which will be undertaken by Commissioner Railway Safety (Northern region).
"Inquiry team will start investigation into cause of accident immediately. All necessary assistance provided to the affected, we are taking care," Prabhu has tweeted.
Poor track maintenance including lack of proper fittings and ballast on the railway lines causes fracture on the tracks.
While a simple crack on track may not be of much concern, a severe fracture causing separation of the track could lead to derailment of trains.
According to railway engineering department responsible for track maintenance, extreme weather condition is the primary reason for rail fractures. While the track breaks due to coefficient of linear expansion in summer, the same happens in winter due to contraction.
However, a senior railway official in Railway Safety wing said lack of proper maintenance is the major reason for rail fracture and weather condition could only aggravate the situation.
TMS (track maintenance service) a new software, has been launched by Prabhu recently to monitor track maintenance round-the-clock.
Despite the Minister's directive, the access to TMS is denied to safety wing and as a result, the monitoring mechanism becomes a closely guarded secret defeating the very purpose of the launching of the software application, the official said.
Though railways have decided to replace all conventional coaches with modern LHB coaches gradually, the process will take time.