As the MP for Biyagama, at the time one of the least developed electorates in the Gampaha district, Ranil started to dramatically change the landscape of the area with brand new carpeted roads, electrification schemes, water and sanitation projects, schools, community centres and other infrastructure inputs befitting a modern model suburb. He established the Biyagama Free Trade Zone to provide employment for thousands of young men and women in a range of industries. From zero in 1977 there were over 100 factories and manufacturing plants established in the area.
Among some of the other projects instituted by him were the Sapugaskanda Industrial Estate, the CEB Thermal Power station, the Sapugaskanda new town, the two new police stations of Sapugaskanda and Biyagama, vocational training schemes, and the Youth Centre at Heyatuduwa. He also allocated land to build the first private sector thermal power station in Sapugaskanda so as to supplement the country’s increasing energy needs. By constructing the Kaduwela / Biyagama bridge, he linked the Parliament Road to Balummahara and opened up a new passage to these areas.
He is also applauded by the local agriculturalists for having introduced new varieties of delicious, fleshy Rambutang to Malwana, through knowledge gained from field trips to Thailand and Malaysia. This led to the expansion in cultivation to other localities as well, and prosperous Rambutang seasons even today.