BAM Nuttall has been appointed as the principal contractor for the £170m overhaul of major rail networks in north and north-east Scotland.
The first phase of the works is expected to be completed by 2019.
As a part of the Scot Rail Alliance - the partnership between Abellio Scot Rail and Network Rail - this Scottish government-funded project will introduce half hourly commuter services between Aberdeen and Inverurie and additional peak time services between Inverness and Elgin.
Over the next four years engineers will:
• Double-track 16 miles of line between Aberdeen and Inverurie
• Build a new station at Forres and straighten the railway alignment
• Extend platforms at Insch and Elgin to accommodate longer trains
• Upgrade signalling systems along the route
• Install infrastructure to allow new stations to be built at Dalcross and Kintore.
Cabinet secretary for infrastructure, investment and cities, Keith Brown, said: ‘Today marks the Scottish Government’s landmark investment package of £170m to improve a key route connecting both northern cities, which will make journeys shorter and more frequent for passengers and freight users.’
Jerry Dickson, operations director for BAM, said: 'Together with our partners AECOM, CH2M, Stobart Rail and Siemens, we are looking forward to commencing work on the Aberdeen to Inverness Enhancement Programme. This essential programme of works will improve connectivity between the major cities of Aberdeen and Inverness, with wider enhancements for the local communities in the north of Scotland.’
Plans for new stations at Dalcross and Kintore are being developed separately by HITRANS and NESTRANS respectively, while a further phase of the Aberdeen-Inverness improvements project is to be developed.
Works are currently on for ground investigation and site survey on the line, main construction works are set to commence early 2016.