Southwestern Japan rail operator Kyushu Railway Co. has filed to list on the Tokyo bourse and is expected to go public in October, a source close to the matter said Friday.

With an expected market capitalization of around ¥500 billion, the listing by the company serving the island of Kyushu would be one of the biggest initial public offerings in Japan this year.

The company, commonly known as JR Kyushu, created from the privatization of the national railway company in 1987, would be the first of three JR companies outside of Honshu to become a publicly listed company.

JR Kyushu filed Thursday to list on the Tokyo Stock Exchange. Given the time typically needed for screening by the bourse, it is likely to list on the exchange's main section in October. The filing came after the company had submitted a preliminary application.

JR Kyushu's core railway operation has been in the red since its establishment as a regional operator. The company expects to be profitable in the rail business in the year ending March 2017 after writing down an asset impairment loss using the fund the government provided to the three regional operators outside Honshu at the time of the privatization.