A TRAIN has derailed at one of Scotland's busiest junctions, affecting rail services across the country throughout the day.

No-one was injured in the derailment of the engineering train in the earlier today at the Greenhill Upper Junction, around three miles west of Falkirk.

The junction is where the main Glasgow to Edinburgh line meets with that heading towards Stirling and Alloa.

The accident and its knock-on to the network comes just 24 hours after work on the main Edinburgh to Glasgow railway line got under way, with passengers expected to face at least six weeks of significant disruption.

The Winchburgh tunnel near Linlithgow in West Lothian will be closed to allow upgrades to be carried out.

The new organisation set up by ScotRail franchise holder Abellio and Network Rail said the derailment had forced some services to Glasgow Queen Street to use alternative routes, impacting upon already lengthened journey times.

A ScotRail Alliance spokesman said: "In the early hours of Sunday morning an engineering train derailed at low speed at Greenhill Upper Junction, north of Glasgow.

"The derailment is a minor incident with only one set of wheels off the rails. The train remains upright and undamaged and there have been no injuries to staff.

"Engineers are on-site working to rerail the wagon and remove the train from the area, but the incident has caused some damage to the track below which will also require repairs.

"We are working to restore normal services as quickly as possible, but the incident is likely to affect trains throughout Sunday."

Work on the Winchburgh tunnel will mainly hit travel between Glasgow, or Stirling/Dunblane, and Edinburgh but it will also have a knock-on effect in areas such as the Fife Circle.

Many passengers will have longer journeys or bus replacements. ScotRail advised passengers to add at least 30 minutes to their planned journey times.

The closure will mean passengers looking to travel end-to-end from Glasgow to Edinburgh will no longer be able to take a train from Queen Street high level platforms, as the trains will only go as far as Linlithgow.

Instead, they will have to switch to the slower Queen Street low level trains or travel on the longer route from Glasgow Central Station.