The British Rail Class 165 Networker Turbo is a fleet of suburban diesel multiple-unit passenger trains (DMUs), originally specified by and built for the British Rail Thames and Chiltern Division of Network SouthEast. They were built by BREL York Works between 1990 and 1992. An express version was subsequently built in the form of the Class 166 Networker Turbo Express trains. Both classes are now sometimes referred to as "Networker Turbos", a name derived some three years later for the project that resulted in the visually similar and EMUs. The class is still in service, now operated by Great Western Railway and by Chiltern Railways. When operated originally by Network SouthEast, along with that operator's Class 166 trains, the Paddington suburban units were initially known as Thames Turbos, while the units operated on the Marylebone suburban network were known as Chiltern Turbos. Description Externally, the class 165 can be distinguished from a Class 166 by the opening hoppers on other window. Class 165/0 Thirty-nine Class 165/0 Networker trains were built in 1990–91, in two batches, for the Chiltern subdivision of Network SouthEast, numbered 165001–039. Both 2-car and 3-car variants were built. Initially, thirty-three units were ordered (comprising the vehicles that made up units 165001-165022 and 165029–165039) but an additional order was placed for a further six units (165023-028). Units 165001-028 were delivered consecutively, as 2-car units, whilst units 165029-039 were delivered as 3-car units. These vehicles have a top speed of . They are now all fitted with tripcocks for working over the London Underground lines between Amersham and Harrow-on-the-Hill, although upon delivery this equipment was only fitted to 165006–028. Automatic Train Protection is also fitted, making them one of the few classes to have both these features in Britain. Each unit was formed of two outer driving motors, with an additional intermediate motor in the 3-car units. The technical description of the formation is DMOSL+MOS+DMOS. Individual carriages are numbered as follows: 58801-58833 (units 165001-022/029-039) and 58873-58878 (units 165023–028) - DMOSL 55404-55414 (units 165029–039) - MOS 58834-58866 (units 165001-022/029-039) and 58867-58872 (units 165023–028) - DMOS Class 165/1 Thirty-seven Class 165/1 Networker trains were built in 1992 for the Thames line subdivision of Network SouthEast, numbered 165101–137. Like the Chiltern units, both 2-car and 3-car variants were built. Units 165101-117 were delivered as 3-car units, followed by the 2-car units 165118–137. They are re-geared and fitted with bogie yaw dampers to