Edinburgh to Glasgow Improvement Programme

The Edinburgh Glasgow Improvement Programme or EGIP is an initiative funded by Transport Scotland on behalf of the Scottish Government to increase capacity on the main railway line between Edinburgh and Glasgow, with new, longer electric trains running by 2017 and full completion in 2019. It is expected to cost £742 million and will be delivered by Network Rail.
The programme was initially announced by the Labour-Liberal Democrat coalition government in 2006, and was continued, although cut back from the original scheme, by the subsequent Scottish National Party governments.
Aims.
The project will deliver the infrastructure to enable 8 car, electric trains to operate (an increase from the previous 6 car maximum) on Edinburgh - Glasgow services with a fastest journey time of 42 minutes.
The additional train carriages will allow a total increase in capacity of 30%.
It will also deliver electrification of 94 miles of track including diversionary routes through Cumbernauld and Falkirk.
Previous proposals.
As originally announced in 2006, the project would have cost £1 billion and aimed to increase capacity by increasing service frequency to 6tph rather than by lengthening trains.
Transport Scotland commissioned Jacobs to examine the project for potential savings and they identified that the a similar capacity increase could be achieved by increasing train length while maintaining a 4tph frequency. This had previously been thought to be impossible due to restrictions at Glasgow Queen Street station. The redevelopment of Buchanan Galleries allowed this option to be developed instead with a major rebuild and the lengthening of platforms at Queen St high level station.
This enabled several major schemes to be dropped from the scope of EGIP as they were only required if an increase in train frequency took place:
Another proposed scheme the Garngad Chord, near had already been dropped from the scheme. It was intended to allow Glasgow-Cumbernauld services to use the North Clyde Line into Queen Street Low Level, thus freeing up capacity on the High Level station. Instead services started on this route in 2014 with a reversal in Springburn, creating a slightly longer journey time.
Electrification to Stirling, and was originally reported to have been dropped as part of the changes to EGIP. Electrification is continuing and is expected to be complete by 2018; it has been carried out under the rolling programme of electrification, rather than as part of the EGIP programme.
Criticism.
The new proposals were criticised by business and environmental groups. Sustainable transport campaign group Transform Scotland described the cuts as 'a major step backwards' and suggested that the government's concurrent decision to bring forward a £3 billion project to dual the A9 road demonstrated a 'perverse set of priorities'.
The fastest journey times between Glasgow and Edinburgh under the scheme will now be 42 minutes compared to the just over half an hour previously promised.
One of the most disruptive elements of the project was the complete closure of Glasgow Queen Street (High Level) for a 20-week period between March and August 2016, to allow replacement of the track in the Cowlairs Tunnel and the lowering of the track bed to accommodate the installation of overhead electrification equipment in the tunnel. ScotRail warned that the diversion works created a potential single point of failure which could paralyse Glasgow's rail network in the event of a train failure or other incident.