Instigated as part of a round of transport improvement projects proposed by the then Scottish Executive in 2003, the plan was to open up a fourth direct railway link between the cities of Glasgow and Edinburgh.

[4] In line with plans to complete the missing part of the M8 motorway, the Executive stipulated that public transport links between Scotland's two largest cities must improve.

In order to permit four trains per hour in each direction, improvements to the existing line have been made: The start of work was signalled with a sod cutting ceremony at Livingston North station in June 2007, attended by Transport Minister Stewart Stevenson.

Drumgelloch, Caldercruix and Armadale were initially served by bus substitution services open due to the inclement weather at the end of November 2010 delaying the completion of minor works (including surfacing of car parks).

Effective 7 March, service between Glasgow Queen Street and Edinburgh Waverley increased to two trains per hour on weekdays, Saturdays and Sunday afternoons.