The five lines are the Traralgon, Geelong, Ballarat, Bendigo and Seymour lines.
A statement said about a quarter of V/Line's Vlocity trains now had mobile signal boosters and the whole fleet would be equipped with the devices by the end of the year.
The Victorian Government is working with Telstra, Vodafone and Optus to complete the $18 million RRCP under which 35 new mobile towers will also be built.
The statement said additionally, in the bid to improve connectivity in regional Victoria, free public Wi-Fi was being provided in Bendigo and Ballarat, 166 new towers were being built to fix mobile black spots, and a $45 million Connecting Regional Communities Program had been launched to address regional priorities.
Victoria's Minister for Innovation and the Digital Economy, Philip Dalidakis, said: “We’re getting on with the job of delivering the mobile coverage that our regional rail passengers deserve.
“Whether passengers want to do business, browse social media or call their loved ones to tell them they’re on the way home, this project will ensure regional passengers are connected.”
“Better mobile coverage on these rail lines is part of our effort to connect regional Victoria and remove the digital divide between those living in Melbourne and those living in our regions," said Regional Development Minister Jaala Pulford.
Public Transport Minister Jacinta Allan said: “We’ve added extra services throughout our regional network, upgrading every regional rail line, and we’re not wasting a minute in giving our passengers better coverage on their journey – we’re getting it done.”