The new girder being less in width as compared to the older girder is now inserted by removing the plates on which the tracks & sleepers rested.The steel/iron plates on the old girder on which the tracks rested were first removed using gas cutters.The new girder is smaller in width as compared to the old one.The new girder will slowly be pushed down into the old girder & the old girder will then be cut using gas cutters after the new girder is completely fixed in its place.