Launched as a key initiative under Digital India programme, the service was kicked off from Mumbai Central station in January 2016, and Dibrugarh in Assam has become the 400th station to go live today, Google said in a statement.
The project has succeeded in its mission of bringing connectivity to millions of unconnected Indians, leveraging on the nationwide optic fiber network backbone created by RailTel, it added.
RailTel is the telecom arm of Indian Railways.
Within the first year of the project's launch, 100 of the busiest railway stations across India were brought online, enabling 15,000 people to experience the internet for the first time every day, it said.
"With over 8 million monthly unique users connecting to the network, this is a lighthouse project for India and every growing economy that is looking to bring the benefit of connectivity to everyone in their country," Google India Director Partnership Next Billion Users K Suri said.
K Manohar Raja, Executive Director (Enterprise Business) at RailTel said the endeavour has been to bridge the experience divide by providing one of the fastest public WiFi networks in the world.
The service, which offers thirty minutes of free access to the internet, saw users consuming about 350 MB of data per session on an average.
While majority of the users are in the 19-34 age group, efforts to help older and first time users with onground support staff has helped millions to experience the internet for the first time, the statement said.