MAJOR rail engineering works at the Winchburgh Tunnel remain "on schedule", Transport Minister Derek Mackay has said as he visited the site to mark the halfway point in the six week project.

Engineers are lowering the trackbed in the tunnel, near Linlithgow in West Lothian, to make way for wires as part of the ongoing electrification of Glasgow-Edinburgh route.

They are also installing more than 1500ft new slab-track on the line to Edinburgh and carrying out preparatory works on the line to Glasgow as part of the £750 million Edinburgh-Glasgow Improvement Programme (EGIP).

The overhaul has forced Network Rail to close the main commuter line between Edinburgh and Glasgow Queen Street High Level, meaning passengers have to use replacement buses or take slower service from Glasgow Central or Queen Street Low Level.

Normal service is due to resume on July 26.

Mr Mackay, visiting the tunnel with ScotRail Alliance Managing Director Phil Verster today [Mon], said the works were on track to be completed on-time and on-budget.

Mr Mackay thanked passengers for their patience, adding: "This week we passed the halfway point of works at the Winchburgh Tunnel and we have now reached the landmark of having more than 50% of the new track laid.

"It is also pleasing to note that the industry management plan for the tunnel closure is working effectively, disruption to services is being kept to minimum, and that the project remains on course to finish on schedule."

Mr Verster added: "This is an incredibly complex piece of engineering work that will help deliver significant benefits to our customers in the future. Once we complete the electrification of the main line between Edinburgh and Glasgow we will be able to run faster, longer, greener trains that will cut journey times and make available more seats on this hugely important route."