couplers. This enables them to work in multiple not only with other units from the same class, but also and the classes of the Pacer and Sprinter families. Accidents and incidents On 4 January 2010, Class 142 diesel multiple unit 142029 collided with a train composed of two Class 159 units at . Nine people were injured. On 31 October 2021, South Western Railway Class 159 unit 159102 collided with a Great Western Railway Class 158 train at Fisherton tunnel in Salisbury. Operations The units were dedicated to the West of England sector of Network South East, operating services between London Waterloo and Exeter; they also worked services between Salisbury and Southampton and on the Reading to Basingstoke line, replacing elderly DEMUs. They then transferred to the South West Trains shadow franchise in readiness for privatisation. Upon the privatisation of British Rail, the West of England route passed in 1996 to the South West Trains franchise, which was won by the Stagecoach Group. Starting in 2000, units were progressively refurbished and repainted from Network SouthEast's blue, red and white livery into South West Trains' express livery. Other post-privatisation modifications included clearer LED destination displays, upgraded air-conditioning, and more openable windows. Currently, the Class 159s operate mainly from London Waterloo to Salisbury/Exeter in formations of six, eight, or nine coaches (2 × Class 159, 2 × 159 plus 1 × 158, or 3 × 159 respectively) and between Salisbury and Exeter in three- or six-coach formations. Until the December 2009 timetable change, some trains continued beyond Exeter to Paignton, Plymouth and Penzance; these usually operated as three-coach units, though at weekends there were some six-coach formations. These services are now operated by the Great Western Railway. The service to Bristol Temple Meads is now also in the hands of Class 159s. Since 2006, the original Class 159 fleet of 22 has been supplemented by eight three-coach 158s (renumbered into the 159/1 series) and 11 two-coach Class 158s. The decision to standardise on 158s and 159s allowed the nine Class 170 'Turbostar' units to be transferred to other operators. Eight went to First TransPennine Express, with the remaining unit going to Southern for integration into Class 171 Turbostars. Refurbishments and conversions Refurbishment of the Class 159/0 2000 South West Trains began a refurbishment programme for its 22 Class 159/0s in 2000. The seats were re-trimmed and interiors repainted. The units were repainted