The Hindu puts the tragedy in perspective:
The attack on the train (technically a special train from which the passengers are transferred at Attari to the India-Pakistan service) has taken place a day before Pakistan's Foreign Minister Khursheed Kasuri arrives in New Delhi for talks on the ongoing peace process. In a bid to signal their strength, terrorists sometimes choose to time their attacks to coincide with the visit of dignitaries. In 2002, Hurriyat leader Abdul Ghani Lone was shot dead in Srinagar a day ahead of Prime Minister Atal Bihari Vajpayee's visit to Kashmir. Two years earlier, 35 Sikhs were massacred in Chattisinghpora in Kashmir on the eve of President Bill Clinton's visit to India. It is more than likely that those who perceive the India-Pakistan peace process as a threat to their survival have perpetrated the Samjhauta Express carnage.It also notes:
The attack may revive memories of the Mumbai train blasts last year, but there is an important difference. The Samjhauta Express is a highly protected train and the attack on it raises serious questions about gaps in railway security. How did the incendiary material used to set the coaches ablaze get past the security checks at Old Delhi railway station?Praveen Swami looks to the Pakistani jihadi press for clues to the motives of the perpetrators.