The Scottish Greens also highlighted slow progress since 2014, with just six more stations being upgraded.
A total of 40 of more than 350 Scottish stations are officially “step-free”, according to a freedom of information request by the party. Others may have platforms accessible via paths.
Funding for lifts and ramps is provide by the UK government, with stations being selected for improvements by the Scottish Government’s Transport Scotland agency.
The Greens said fines imposed on ScotRail for failing tough service quality standards could also be used.
Transport Scotland said Network Rail had completed access upgrades during its five-year spending period to next March at Blairhill, Elgin, Hamilton Central and Westerton, with Kilmarnock and Kilwinning also due to be completed by then.
Improvements are also planned at Pitlochry, Aviemore and Nairn.
Greens transport spokesman John Finnie said: “The travelling public, including people with mobility issues and families using buggies and prams, deserve an easily-accessible network as our railways are a public service.
“The Scottish Government is moving too slowly on this issue. Indeed, there’s an irony as the financial penalties incurred by ScotRail for poor performance help fund the necessary improvements.
“We clearly shouldn’t be relying on a poor rail service to generate the cash for step-free stations and platforms.”
A spokesman for the UK Department for Transport (DfT) said: “We are determined we remove any barriers faced by disabled people.
“We know there is more to do – that is why this year we launched the inclusive transport strategy, which aims to make the entire transport network accessible by 2030.”
The DfT said it expected to announce in April the next station upgrades, having received nominations last month.
It said £300 million would be spent on the work across Britain from 2019 to 2024.
A Transport Scotland spokesperson said: “We have worked closely with ScotRail and Network Rail in developing a nomination list for stations, which has now been submitted for consideration.
“The Scottish Government funds significant accessibility improvements across Scotland, with further schemes under consideration.”