extended in 2005 to , but in 2018 the service was cut back to due to overcrowding and a shortage of additional diesel stock. Services on the to branch of the Oxted Line were later also transferred to Turbostar operation. Services from London Bridge to Uckfield went over to Turbostar operation in late 2004. The Ashford-Eastbourne service, as well as peak-time Ashford-Rye and Ashford-Hastings shuttle services, are nearly always operated by the two-car Class 171/7; the four-car Class 171/8 units occasionally appear on the route during special events such as the Rye bonfire celebrations. The Uckfield-London Bridge and Uckfield-Oxted services use both the two-car and the four-car units. These units are often coupled together, forming six-car, eight-car or ten-car trains following platform extensions at Uckfield line stations. Future As at August 2022, Southern operated 20 sets; 12 two-carriage sets and eight four-carriage sets. In September 2022 the two Class 171/2 and two Class 171/4 sets were reformed back into their original three carriage formations, returned to Eversholt Rail Group and leased to East Midlands Railway (EMR). Three moved to EMR where they will be converted back to Class 170s while the fourth will remain on sub-lease with Southern. Further reshuffling will result in Southern having a fleet of four two-carriage and 13 three-carriage sets by December 2022. In September 2022, 171202, 171401 and 171402 were transferred to East Midlands Railway and renumbered to 170422, 170423 and 170424 before being renumbered to Class 170s/9s. Fleet details Initial deliveries took place when the original two-car units, at the time classified as Class 170/7, entered service in 2003, followed by the four-car Class 171/8 units in 2004. At this time, the two-car sets received their Dellner couplings and were reclassified as Class 171/7. In 2015, four thre-car Class 170/4 units were transferred to Southern from First ScotRail to enhance the fleet; two of these had the centre car removed and added to the remaining two, to form a pair of two-car and a pair of four-car units. With the addition of Dellner couplings, the new units were reclassified as Class 171/2 and 171/4. Formation of two-car Class 171/7: DMOCL(W) + DMOSL Formation of four-car Class 171/8: DMOCL(W) + MOS + MOS + DMOCL References External links Bombardier Transportation multiple units 171 Train-related introductions in 2003