British Rail Class 165

British Rail Class 165 Network Turbo
Chiltern Railways refurbished Class 165/0 No. 165017 at Aylesbury
The refurbished interior of a Chiltern Railways Class 165/0
In service	1990 - present
Manufacturer	BREL York
Constructed	1990 - 1992
Refurbishment	2003–2005 (165/0)
Number built	39 trainsets (165/0) 37 trainsets (165/1)
Number scrapped	1 trainset (due to the Ladbroke Grove Rail Crash)
Formation	2 or 3 cars per trainset
Fleet numbers	165001 - 165039 165101 - 165137
Operator(s)	Chiltern Railways Great Western Railway
Line(s) served	Great Western Main Line and branches Chiltern Main Line and branches
Specifications
Car body construction	Welded aluminium
Car length	DMS/DMSL - 22.91 m (75 ft 2 in) MS - 22.72 m (74 ft 6 in)
Width	2.81 m (9 ft 3 in)
Height	3.79 m (12 ft 5 in)
Maximum speed	75 mph (121 km/h) (165/0) 90 mph (145 km/h) (165/1)
Weight	2 Car - 74 tonnes (73 long tons; 82 short tons) 3 Car - 111 tonnes (109 long tons; 122 short tons)
Prime mover(s)	One per car, Perkins 2006-TWH Diesel
Power output	350 hp (261 kW)
Transmission	Voith Hydraulic T211r 2 axles driven per car
Safety system(s)	AWS, TPWS ATP, Tripcock system (165/0)
Coupling system	BSI
Multiple working	Class 166, Class 168
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge

The British Rail Class 165 Turbo is a fleet of suburban diesel multiple units (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. The trains were originally known as Network Turbos. An express version was subsequently built in the form of the Class 166 Turbo Express trains. Both classes are now sometimes referred to as "Networkers", a name which was derived some three years later for the project that resulted in the visually similar Class 465 EMUs.

The class is still in service, and is now operated by Great Western Railway on services out of London Paddington station and by Chiltern Railways on services out of London Marylebone station. When operated originally by Network SouthEast, along with that operator's Class 166 trains, the Paddington suburban units were initially known as Thames Turbos, whilst the units operated on the Marylebone suburban network were known as Chiltern Turbos.

Two batches of units were built for different subdivisions of Network SouthEast to replace elderly "Heritage" DMUs as well as locomotive-hauled trains on services out of London Paddington and London Marylebone. The fleet is wide-bodied to take advantage of the loading gauges of the former Great Western Railway and Great Central Railway on whose lines it runs.