Patiala, Jan. 25 -- An explosion damaged a railway track and a freight engine and left a railway staffer injured near Sirhind at 9.50 pm on Friday, just days before Republic Day, raising fears of a sabotage attempt amid heightened security arrangements. On Saturday evening, the country's premier counter-terrorism agency, the National Investigation Agency (NIA), joined the probe after being alerted by the Punjab Police. Khalistan Zindabaad Force (KLF), a Khalistani militant organisation, claimed responsibility for the blast. P2...