FirstGroup flew chief executive Tim O'Toole into Scotland specially yesterday to unveil the report which says Scotland's rail network injects £1.22billion a year into the tourist industry.
It comes weeks ahead of the decision on a new era for ScotRail , where ten-year operator FirstGroup is up against four other short-listed bidders for the £6 billion franchise.
The study from Strathclyde University's Fraser of Allander Institute follows a similar exercise last September which found £1.55 billion a year is injected into the economy as a whole by ScotRail, which has increased its own headcount by 35 per cent since FirstGroup won the franchise from National Express in 2004.
Mr O'Toole said: "What this report tells us is we have been an enormous supporter and enabler of tourism in this country.
"We get caught up in the life of the commuter and moving population around so they can work, but this report reminds us that over half of our (passenger) volume supports the tourist industry."
Leisure trips accounted for 42 million passenger journeys in 2012 or 54 per cent of ScotRail's business.
Mr O'Toole added: "We are anticipating a busy summer ahead with the Commonwealth Games in Glasgow and the Ryder Cup at Gleneagles. This is about emphasising the point that we, the government, and Transport Scotland, have been great partners and we continue to deliver for Scotland."
The report says "substantial new rail investment has taken place due to Glasgow 2014" and ScotRail expects to provide 1.1 million rail trips for Commonwealth Games events, as well as transporting 40,000 people to and from the Ryder Cup at Gleneagles.
It found ScotRail supports 37,721 jobs throughout Scotland.
Transport minister Keith Brown welcomed the report and said Scotland's railways are "enjoying a massive resurgence in popularity".
He added: "We want to capitalise on the undoubted potential for tourism across the many routes across Scotland and encourage operators to come forward with proposals to promote and facilitate the development of tourism using the rail network, as well as enhancing the scenic opportunities for passengers to make our rail journeys as good as our marvellous destinations."
In the tender for the new seven-year franchise, to be decided in September, the government also set a 42-minute journey time between Glasgow and Edinburgh, accelerated services to Stirling, Perth, Dundee, Inverness and Aberdeen, a smart ticketing system, sub-inflation rises in off-peak fares, and conditions on apprentices and the living wage.
The incumbent operator faces competition from four rivals, two of them led by former FirstGroup executives.
National Express's bid is led by highly-regarded former ScotRail managing director Mary Grant, while Hong Kong-based MTR has recruited Jeremy Long, who also oversaw ScotRail in his time at FirstGroup. The other bidders are Dutch state-owned rail firm Abellio, and German- owned Arriva, which runs the Cross Country franchise.
Mr O'Toole said: "We can't worry about whatever someone else promises - we have a railway which has been the leader throughout the UK consistently and has recently turned in record punctuality."
Steve Montgomery, managing director of ScotRail, said the report underlined the "major advances we've made since taking over the franchise" in enhanced services and facilities, environmental performance, and community activities.
Malcolm Roughead, chief executive of VisitScotland, said: "This report reinforces the value of the tourism sector and the role of providers such as First ScotRail in ensuring that the Scottish tourism industry carries on creating jobs, sustaining communities and boosting the wider Scottish economy."
Meanwhile Mr O'Toole, under fire from activist shareholder Sandell for taking his bonus this year after two years of refusing it, said: " I do believe this is the inflection point for the company, and this year we have given positive returns to shareholders, so I didn't think the gesture which in the prior two years was intended to understand the sacrifice they were making was any longer appropriate."