"Samjhauta" Thwarted: Another Senseless, Horrible Bombing

It's difficult to know what to say sometimes after terrorist attacks like the recent bombing of the Samjhauta Express. 68 innocent people lost their lives -- and for what? If it turns out to be an attack planned by Kashmiri militants or other Islamists, this kind of attack seems particularly bizarre, as it appears that the majority of the people who died were in fact Pakistanis. (If another motive or ideological agenda was behind the attack, it's not as if it would be any better.) And needless to say, if this follows the pattern of some other recent terrorist attacks in India, it's entirely possible -- likely, even -- that weeks will go by without any satisfactory answers appearing. (I'm perfectly happy to be proven wrong if this turns out not to be true.)

Here are some of the issues I've seen people discussing with regards to this attack:

• At Outlook, there is an interesting article that describes in depth the general lack of security on the Samjhauta Express train. Hopefully, both governments are going to seriously revamp this.
  
  
• A big question that people are asking is, were the doors locked from the inside, preventing people who survived the original explosions from escaping the two burning cars? Some witnesses have claimed they were, but India has denied it. At Bharat-Rakshak, however, I came across a commenter who has a good explanation for why this might have been done:
  
  

  In north India, when travelling overight, train compartments are usually locked from inside to prevent entry of people who do not have reservations in that compartment. The TT opens them at stations to allow entry only the passengers that belong to that compartment.
  
  With intense heat, the locked door latches must have jammed. It is difficult to open these latches even otherwise. Women and kids have to ask other passengers to help then open the door.
  
  The windows in trains are barred to prevent 'chain snatching' and other types of burglaries. (link)

  
  
  Those sound like good reasons, but I hope after this tragedy officials are thinking about possible failsafe mechanisms, so nothing like this happens again.
  
  
• Sketches have been released of the suspects. They were apparently speaking the "local Hindi language." That doesn't tell us much, however.
  
  
• What was the explosive used? The bombs are being described as IEDs with kerosene and other "low intensity" fuels -- in other words, not RDX or other material obtained through transnational networks. These sound like materials that are very easily available, but still incredibly deadly for people in a confined space. A witness at the BBC mentions that the explosions did not force the conductor to stop the train right away -- indeed, he may not have known about them until several minutes after the fires started.