The exchanges in the Scottish Parliament follow The Scotsman revealing last month that 300 daily services suspended because of the Covid crisis would not be restored under a planned major timetable change in May next year because of lower demand.
The moves – which are out for public consultation – would reduce the total number of weekday trains from 2,400 before the pandemic to 2,100.
It follows Scottish Government for ScotRail doubling to nearly £1 billion a year after passengers fell by up to 95 per cent during the coronavirus lockdowns.
South Scotland Labour MSP Colin Smyth, who called for the threatened cuts to be lifted, said: “We won’t get people back on our trains by taking that train away.”
Transport minister Graeme Dey replied: “It is frankly baffling that a member of Parliament can call for a never-ending increase in services with no consideration for the cost.”
He pointed out the plans included about 100 more services a day than were currently running, including on the Glasgow-Dumfries-Carlisle route.
Mr Dey said: "ScotRail has examined pre-Covid and expected future demand and developed the proposed timetable that seeks to match service patterns with uptake, with scope for additional capacity whilst recognising the need for financial and environmental sustainability.
"The proposed timetable is a new starting point, not the end point.
"It has been designed to accommodate pre-pandemic levels of demand whilst removing much of the unused capacity on the network.
"As more people return to using rail, further services that there is demand for will be introduced."
Mr Dey added: “I have yet as a parliamentarian encountered any set of draft proposals which are perfect or indeed are not ultimately amended in some form.
"But we have to be realistic – we cannot run services which are little utilised.”
Scottish Conservatives transport spokesman Graham Simpson asked him: “Is this a taste of things to come when ScotRail is nationalised [in April]?”
Mr Dey said: “The direction of travel that has been set by this government is very clear – investment in rail, decarbonisation of rail and a great deal of support for rail.”