Ferry operator Caledonian MacBrayne's board has had initial discussions on running Scotland's train services.
The detail was revealed by CalMac bosses while giving evidence to MSPs in Holyrood about disruption to its ferry services in recent months.
David McGibbon and Robbie Drummond were asked if ScotRail was to be publicly-run, would CalMac make a bid.
They said the board had discussed it and the firm had indicated to Transport Scotland it was willing to talk.
Mr Drummond stressed there were "a lot of questions to be answered" about running train services before "deeper discussions" could take place.
'Exploring the possibilities'
The contract to run ScotRail, currently held by a private operator, could potentially become available in 2020.
Mr McGibbon told MSPs that the idea of CalMac, a company owned by Scottish Ministers, running train services had already been dubbed Caledonian MacTrain by a newspaper.
But he went on: "We want to expand the group in terms of ports and harbours and ferry services both nationally and internationally.
"As far as rail is concerned, we don't have any experience on rail, but in terms of developing the group we would be interested in exploring the possibilities and the board's discussed that, but only that."
Mr McGibbon added: "We need to know an awful lot more about it, what it entailed and what the cost would be.
"But we would be interested, without any commitment, as a public sector body to look at it."