Thackley tunnel is a railway tunnel on the Airedale Line from Leeds to Shipley then on to Bradford or Skipton. Completed in 1846 and opened on 30 June that year, the tunnel is approximately 1,300 yards (1,200 m) long and cut through the prominent Thackley Hill to reduce travel time. The contractor chosen to build the Tunnel was James Bray, an iron and brass founder from Leeds who later contracted the construction of the Bramhope Tunnel on the Leeds to Thirsk main line.
Originally there was just one Tunnel bore but in 1900 the line was increased to four tracks and a second tunnel bore was built, one carrying the Fast lines from Leeds and the other the Slow lines. The Southern tunnel was closed in 1968 coinciding with the final closure of the Great Northern Branch Line from Shipley to Laisterdyke via Idle and Thackley. At the Western mouth of the Tunnel stood the original Idle station (albeit closer to Thackley than Idle), which opened in 1847 and closed the following year in 1848.
In the 1970s and the 1980s, the closed original tunnel was backfilled with spoil due to distortion of the tunnel lining 
- In 2003 Russell Trueman, councillor for Thackley decided to erect a fence round the surrounding area of the tunnel to stop people climbing onto the train tracks.
- In 2010 Thackley resident Harry Hurrell petitioned for its closure due to safety reasons