Network Rail is looking for bids for a £400 million electrification project in Scotland.
The Edinburgh Waverley-Glasgow Queen Street line is set for a major overhaul, which will include station upgrades at Waverley, Queen St, Croy, Falkirk High, Polmont and Linlithgow.
Bosses at the firm hope to award contracts for the work in early 2014 and are looking to have the job done by 2016.
Billions of pounds have been earmarked for the electrification of the rail network throughout the UK and this will result in faster, more efficient services for passengers.
Transport minister Keith Brown said Network Rail's latest announcement - which forms part of the £650 million Edinburgh-Glasgow Improvement Programme - is good news.
"The electrification of our busiest route will deliver significant improvements in rail journey times and train capacity," he commented.
David Simpson, Network Rail route managing director for Scotland, said this is a "unique chance" for the organisation to "modernise and enhance" rail services across the central belt.