What led to Mysuru-Darbhanga train's collision, which injured 19 people in TN?

Mysuru-Darbhanga Bagmati Express train collided with a goods train, injuring 19 people, after it mistakenly entered a loop line, South Railway General Manager RN Singh said. The train was supposed to pass without stopping at Tamil Nadu's Kavaraippettai station. "It was unusual that despite having signals for main line, train entered loop line, where goods train was standing," Singh added.