GUWAHATI: The officers and staff of NF Railway, Construction Organisation observed the 63rd “Mahaparinirvan Divas” of Bharat Ratna Dr. Ambedkar in the HQ premises at Maligaon on Friday. N F Railway, Construction General Manager, NK Prasad paid homage by lighting a lamp and also by floral tribute on the occasion of 64th “Mahaparinirvan Divas” of great leader and architect of Indian Constitution Bharat Ratna Dr. B R Ambedkar.