In 1851, a vast amount of ironstone was discovered in Northamptonshire. As a result of this the London & North Western Railway, (L&NWR), decided to capitalize on this occurence by propsing a new railway line between Northampton and Market Harborough. This in itself would open up more of the countryside for rail travel by providing a link between the lines from Rugby to Stamford, and Blisworth to Peterborough.
The contract to build the line was eventually awarded to Richard Dunkley of Blisworth, Northants, on the 23rd. July 1856, five years after the original proposal.
The completion date for the line was given as the 1st. June 1858. However, due to unforseen difficulties, one of which was a landslide in March 1858 at the north face of Kelmarsh tunnel, the line was not finally approved for public use until the 15th. February 1859, with the first passenger train running the following day.
The line was originally built as a single track to begin with, but as the volume of traffic increased, it was decided that a double track was needed. This gave rise to the unusual site of both Oxendon tunnel, (462 yards long), and Kelmarsh tunnel, (322 yards long), having seperate bores for both the northbound and southbound lines.
Passenger services dropped significantly after the Second World War, leading to Spratton station being closed first in 1949, closely followed a year later by Pitsford & Brampton station.
Passenger trains ceased altogether on 4th. January 1960, when the remaining stations between Northampton and Market Harborough closed.
Although the line was officially closed, the Royal Train was known to have stopped overnight, on several occasions, at the sight of the former Lamport station. The station house at Lamport was sold into private hands in the late summer of 2002.
As ironstone workings in Northamptonshire declined, it became clear that the line no longer justified the running costs, and so it was formerly closed on Sunday 16th. August 1981. The day before closure a Diesel Multiple Unit was hired to make the final run between Northampton and Market Harborough.