Network Rail is warning of major disruption on Easter weekend.
A programme of engineering works will get underway, with Glasgow set to be one of the worst affected areas.
The works, which will also be carried out in the north east of the country, are part of the first phase of a five-year plan to improve the rail network.
£4 million of signals and points upgrades will be installed at Shawfield which is set to cause major delays at Glasgow Central.
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Liam Sumpter, chief operating officer for Network Rail Scotland, said: "This investment programme is vital for the future of Scotland's railway.
"It will help to improve reliability on the west coast main line - one of Europe's busiest rail routes - and prepare the way for a significant improvement in services for customers in the north east of the country.
"The work we are undertaking this weekend will help to provide a more modern and more reliable railway.
"We understand the inconvenience this work will cause some customers, but such a significant investment cannot be delivered without temporary disruption and every effort has been made to reduce the impact of our activities as much as possible."
Engineers will also replace or refurbish seven bridges between Aberdeen and Inverurie and will renew tracks and a level crossing to improve under-line drainage between Beattock and Abington, on the west coast main line in South Lanarkshire.
The works will be carried out from this Saturday April 20 to Monday April 22.
