Commuters face five months of travel misery with the closure of a main train station for 20 weeks.
Scotrail has announced the Queen Street tunnel at the Glasgow station will shut from March 20 to August 8 this year for vital repair works.
Trains normally running in and out of the station’s High Level will have to be rerouted to either Queen Street Low Level or Glasgow Central Station.
As a result, there will be changes to existing timetables and longer journey times.
Scotrail said the £60m project will renew nearly 2km of ageing slab-track through Queen Street tunnel and enable faster, longer trains to operate on Scotland’s rail network from later this year.
A dedicated webpage launched on Tuesday to give people information about how the closure will affect their journeys.
Over the coming weeks there will also be customer information at stations and on trains. Full timetables will be available to download from February 20.
Additional carriages will be added to services to provide additional room for passengers and queuing systems will be in place at Glasgow Queen Street and Edinburgh Waverley at peak times.
Phil Verster, managing director of the ScotRail Alliance, said: “Upgrading the tunnel will allow us to run faster, longer, greener trains in the future. This will mean more seats, shorter journey times and less impact on our environment.
“The long term benefits of this investment will be considerable, not just for our railway, but also for the country.”
Transport Minister Derek Mackay said: “This is a significant milestone in our £5bn programme of investment in Scotland’s Railway which is helping to reverse decades of under-investment and substantially modernise our rail infrastructure.”