NEW DELHI — Security has been tightened at major railway stations across north India following a Lashkar-e-Tayyaba (LeT) threat to attack railway stations during Holi next week. A letter from the militant outfit threatened to strike during Holi, which falls next Saturday, railway officials said. At the time of festivals, railway stations across the country are crowded with mainly migrant passengers, who visit their hometowns."A letter in the name of Lashkar-e-Tayyaba was received by railway officials in Hapur, Uttar Pradesh, six days ago, claming that an attack would happen at New Delhi, Ghaziabad, Meerut and other railway stations during the upcoming Holi festival," Rajiv Saxena, a senior northern railway official, told IANS yesterday. "Keeping in view the passenger flow, we have alerted the investigating agencies and adequate security measures have been taken. We get such threats every year, mostly at festival time, but no compromise on security is made," Saxena added.