Patna: East Central Railway (ECR) observed the 75th Constitution Day at a simple function held at the ECR headquarters in Hajipur and other divisional headquarters of its five divisions—Danapur, Sonepur, Samastipur, Pt Deen Dayal Upadhaya and Dhanbad. The city-based AN College and other institutions of the Patliputra University also observed the Constitution Day and highlighted importance of the occasion, sources said.