The popular Puffing Billy tourist rail line will get a $6.5 million upgrade if the Turnbull government is re-elected, just $3.5 million less than the federal government's contribution to the $10.9 billion Melbourne Metro rail project.

Prime Minister Malcolm Turnbull rode the popular tourist line in the Dandenong Ranges on Wednesday morning before announcing that if re-elected, $6.5 million would be spent upgrade the Puffing Billy service, including construction of all-weather facilities and restoring old rolling stock.

The Victorian government is building a new rail line between South Yarra and South Kensington under the city and has been calling for federal funding, especially from the public transport-loving Prime Minister.