The first stage of a major north-east rail project is on track to be completed in August, according to those behind the work.
Network Rail is currently carrying out work for the double tracking of the Aberdeen to Inverness line, in a bid to increase the amount of trains on the route.
The first phase is expected to be finished in August, with customers expected to see improvements to rail services in December, when new timetables come into force.
Work to be carried out includes installing 16 miles of new track, 40,000 new signals, 120,000 tonnes of ballast and 19 bridge improvements, including the Don Viaduct and Canal Road bridges in Port Elphinstone, Inverurie, which will accommodate increased loads and additional rail track.
Graeme Stewart, senior sponsor at Network Rail, said: “The improvements will start being introduced in December, it’ll be the big bang.
“It’s going to increase services between Aberdeen and Inverurie by a significant amount.
“The doubling of the track will let more trains run. There’ll be 27 inter-city service trains as well.”
The inter-city services will visit stations such as Dyce, Inverurie, Stonehaven and Montrose.
Work will be carried out at the weekend, with more continuing next month.
Keep up to date with the latest news with The Evening Express newsletter
From May 4 to June 14, there will be a six-week closure between Dyce and Inverurie, which will be served by buses instead. From June 15 to August 9, an eight-week closure will take place from Dyce to Huntly.
A further three days of rail replacement services will operate between Aberdeen and Inverness from August 10 to August 12, and the final one will be for six days between Aberdeen and Huntly, from August 13 to 19.
The blockades, which is a complete stopping of services, follow on from similar works last year.
Billy McKay, operations programme manager, added: “We’re on programme, we’ll be busy this weekend and next weekend, and on May 4 for 15 weeks.
“The blockade last year was a massive success, and there were significant comprehensive lessons learned. We’re in a very strong position.
“There’s a lot of advance works, that’s why these two weekends are key to us, we’ll be doing a massive amount of work.”
Phase two will focus on the creation of two new stations, at Kintore and one at Inverness Airport.