The list of prospective bidders includes incumbent operator VR Group and Swedish national train operator SJ, as well as First Rail Holdings, Go-Ahead Group and the Swedish subsidiaries of Arriva, Transdev, and MTR Corporation.
HSL says all seven participants met its eligibility requirements for the tender, including a license to operate commercial rail services in at least one European country.
The final call for tender will be issued to the shortlisted bidders in May 2019 and a preferred bidder will be announced in April 2020, with the contract beginning in June 2021.
The agreement will cover the operation of around 7 million train-km a year on the Helsinki Ring Rail, Helsinki - Siuntio, and Helsinki - Kerava lines.
The contract will have a minimum duration of 10 years, with options to extend the term by up to three years or cancel the agreement three years before expiry. This will enable HSL to accommodate the construction and commissioning of the Helsinki City Rail Loop.
The winning bidder will use the fleet of 81 Stadler Sm5 EMUs owned by leasing company Junakalusto and will also be responsible for maintaining the trains.
In February 2015 HSL directly awarded VR Group a five-year transitional contract after deferring plans for competitive tendering.