GUWAHATI, Aug 13: Heavy rainfall in the last 48 hours in West Bengal, Bihar, Assam and other NE states has resulted in railway operations being severely hampered as rain water has affected railway tracks at several places in Katihar and Alipurduar Division of N. F. Railway. Railway lines were affected at as many as 12 locations initially, of which seven were already repaired and restored, a press release said. Trains cancelled on August 14 are 15903 Dibrugarh-Chandigarh Express and 15636 Guwahati-Okha Express. While as many as twenty trains were cancelled on August 13, as many as four Up trains and ten down trains remain stranded at various locations. Stranded passengers in various stations were provided all possible basic amenities by the local Railway authority and the trains filled up with water at nearest possible watering points, the release added.