The 133 km (83 mi) railway line begins at Ragama junction and runs through the major towns along the north-west coast of the country, through to Periyanagavillu.

The line starts from Ragama and runs through the towns of Kandana, Ja-Ela, Seeduwa, Katunayake, Negombo, the line becomes single-track from this point onwards, and passes through, Lunuwila, Naththandiya, Madampe, Chilaw, Bangadeniya, Mundel and ends at Puttalam.

The Negombo railway station was opened on 1 December 1909, with the line extended to Chilaw in 1916.

[4][6][7] In 1943 the track from Bangadeniya to Puttalam was removed, as the rails were required on other strategically important routes due to shortages caused by World War II.

In 2017 the government commenced investigating the feasibility of extending the rail line from Puttalam via Norocholai power station (servicing the country's main coal power plant) to Mahawa, connecting the Northern and Puttalam lines.