Scotland's rail users promised 200 new services and 20,000 more seats
Rail passengers in Tayside, Stirlingshire, Perthshire, Aberdeenshire and the Borders are being promised a "revolution" in travel.
It is said to result from ScotRail's plan to introduce 200 new services, providing 200,000 additional seats each day.
The timetable changes are the result of the Scottish government's decision to retain 13 Class 170 diesel trains.
Public transport campaigners have welcomed the announcement.
However, they insisted additional track capacity would be needed if the Scottish government was to meet its promise of "the largest programme of benefits to rail passengers seen in a generation".
'Service will be unrecognisable'
Scotland's Transport Minister Derek Mackay said: "From 2018 passengers will benefit from more seats, more services and faster journey times as a direct result of the increased funding that we are putting into the rail network.
"The retention of these units will complement the arrival of our new High Speed Trains, which will allow for new and improved intercity connections.
"They will also make our rail network more resilient, creating opportunities to run faster services on key commuter routes and offering better connectivity for regional areas."
Phil Verster, Managing Director of Abellio ScotRail, described the announcement as "a really significant moment in our mission to transform Scotland's railway".
He added: "In three years' time, the service that we provide to our customers will be unrecognisable."
The plan also promises;
- a new electric fleet running between Glasgow and Edinburgh
- high speed trains linking Scotland's cities
- 200 new services
- 20,000 more seats, particularly in Aberdeen, the North East and Fife.
Colin Howden, from public transport campaign group, Transform Scotland, welcomed the announcement, but he said unless there were "concrete commitments" to upgrade routes then the network might not be able to take the added services.
Call for Edinburgh to Perth direct route
He explained: "It's certainly going to be difficult to get more trains on the route from Dundee to Aberdeen unless there is a clear and transparent decision by government to upgrade the single track rail line at Montrose.
"Services from the Edinburgh to Perth are severely constrained by capacity limitations on the Fife Coast and the long single track section on the approach to Perth.
"In our view, the most significant single improvement that could be made would be the re-creation of a direct route from Edinburgh to Perth.
"This would not only dramatically change journey times from Perth and Inverness to Edinburgh but would also reduce journey times from Aberdeen by routeing some trains via Perth. That would represent a 'rail revolution' for the Scottish inter-city network."
Sarah Beattie-Smith, from the Scottish Greens, welcomed the plan to increase services but claimed it was not enough.
She said: "The SNP seems to think that tinkering with train service numbers is enough to fix Scotland's broken public transport system. Don't get me wrong - new rail services are all well and good, but this policy falls far short from the 'rail revolution' the Scottish Government wants to brand it as.
"To properly support the people who are currently isolated by our poor and expensive public transport, we need to do much, much more."