The Scottish Government has agreed to match a £50m offer to safeguard and improve the cross-border sleeper train service.
Transport Minister Keith Brown said the Scottish commitment will surpass the total from the UK Government.
It comes during a consultation on the future of train services north of the border, including suggestions that funding for the sleeper could either be improved or withdrawn.
Despite the option to cut funding, the SNP administration said it was always the intention to continue and improve the service, which connects Inverness, Aberdeen, Fort William, Glasgow and Edinburgh with London.
Mr Brown said: "I am delighted to now confirm that we have submitted proposals to the Treasury that will see us invest, as a minimum, £50m to ensure that the Caledonian sleepers are enhanced to offer better facilities and a more responsive service to passenger needs.
"This comes on top of our already record levels of investment in Scotland's railways, including the Edinburgh to Glasgow improvements programme and Borders railway.
"I now await the decision of the Treasury on whether it will stick to its promise and make the funding available to maximise the improvements to the service.
"That ethos of offering the best possible experience for passengers is at the heart of our current Rail 2014 consultation, which gives passengers the opportunity to have their say on how our trains operate beyond the current franchise which ends in 2014.
"For this reason, I would urge everyone with an interest in Scotland's railways to participate in the consultation and play their part in shaping the future of our rail services."
Chancellor George Osborne made the initial £50m offer as part of his Autumn Statement last month.
The Caledonian Sleeper service provides two services each night, except Saturdays, between Scotland and London.
It costs about £21m a year to run, excluding the track access costs.
The Transport Scotland consultation document states: "Overall we consider that there is the potential to improve the longer-term financial performance across all the sleeper service routes, through investment in services and rolling stock.
"We are considering a number of options for the future provision of sleeper services, for instance: removing or increasing financial support, and reducing the provision, either through removing the Highland or Lowland service, or by running the Lowland services to and from Edinburgh only."