Patna: The railway`s safety panel on Saturday began its inquiry into Wednesday`s derailment of the Delhi-Dibrugarh Rajdhani Express in Bihar`s Saran district that claimed four lives and injured 22 others. "Commissioner of Railway Safety (Eastern Circle) PK Vajpayee visited the site of derailment in Saran district and began the inquiry," railway official AK Razak said. Twelve bogies of the Delhi-Dibrugarh Rajdhani Express derailed early Wednesday at Bishanpur village near Goldenganj railway station in Chapra, district headquarters of Saran. "Vajpayee visited the accident site and recorded statements of gatemen at railway crossings between Gaitamsthan and Goldenganj on the Chapra-Sonepur rail section," Razak said. Vajpayee also recorded the statements of the loco pilot, assistant loco pilot and guards of Rajdhani Express and Kavi Guru Express, which passed on the same track barely half an hour before the derailment. According to railway officials, Vajpayee talked to Chapra Kachhari station master BN Pathak who received the first message from the gateman of Bishunpura crossing. "Vajpayee assessed the track maintenance in this section," officials said. Another railway official, not willing to be named, told a news agency Vajpayee has not revealed anything like likely sabotage or Maoist hand or any technical fault behind the derailment after he visited the site and held discussions with officials concerned. "He will go into all details as it is mandatory for him to explore all possibilities," he said. The Bihar government had already ruled out involvement of Maoists in the derailment and blamed poor maintenance of tracks as the cause.