There was a tragedy. A complete compartment got burned. People died.
OR
There was a conspiracy. A bogie was meticulously burned and its passengers killed.
Be it either ways. What should a government do? Try and get the situation under control, immediately, using all the available resources. Using all available resources, find the cause of the incident. If it is a tragedy, provide succor to the bereaved. If it was a conspiracy, hunt down the accused and put them on trial.
What did actually happen? And therein lies the tragedy. All your short-sighted comments about sob-nobody-talks-about-Hindus-being-killed and Muslims-started-it and Muslims-deserve-it and other very similar comments look eerily like a well oiled plan to not discuss the real issue at all.
You can fool some people all the time, all the people some time but not all the people all the time.