British Rail Class 171

British Rail Class 171 Turbostar
Southern Class 171/7, no. 171 727 at Lewes railway station, with a service from Brighton to Ashford International
Interior of a Class 171 featuring a customer information system display
In service	2003 - Present
Manufacturer	Bombardier Transportation, Derby, UK
Family name	Turbostar
Replaced	Class 205 (Marshlink Line) Class 207 (Uckfield Line)
Constructed	2003 - 2004
Number built	16 trainsets
Formation	2/3/4 cars per trainset
Fleet numbers	171 721 - 171 730 171 801 - 171 806 171 921 - 171 924
Capacity	107 seats (2 Car) 241 seats (4 Car)[1]
Operator(s)	GTR Southern
Specifications
Car length	23.62 m (77 ft 6 in)
Width	2.69 m (8 ft 10 in)
Height	3.77 m (12 ft 4 in)
Maximum speed	100 mph (160 km/h)
Weight	Class 171/7: 90.41 tonnes (88.98 long tons; 99.66 short tons) Class 171/8: 176.21 tonnes (173.43 long tons; 194.24 short tons) Class 171/9: 176.21 tonnes (173.43 long tons; 194.24 short tons)
Prime mover(s)	One MTU 6R 183TD diesel per car
Power output	422 hp (315 kW)
Transmission	Voith Hydraulic T211rzze 2 axles driven per car
Braking system(s)	Air[1]
Safety system(s)	AWS, TPWS, GSM-R
Coupling system	BSI coupling replaced by Dellner coupling
Track gauge	1,435 mm (4 ft 8 ^1⁄2 in) standard gauge

The Class 171 Turbostar is a type of diesel multiple unit (DMU) train built by Bombardier Transportation (previously ADtranz) at its Litchurch Lane Works in Derby, England, which is identical to the Class 170, except for the replacement of the BSI (Bergische Stahl Industrie) coupler with a Dellner coupling. This provision was made to allow emergency joining with Class 377 DC third-rail electric units. The vehicles work on the southern regions of the British railway system, operating services from London Bridge to Uckfield and from Brighton to Ashford International, these routes being unelectrified between Hurst Green and Uckfield and Ore and Ashford International, respectively.

The fleet are operated by Govia Thameslink Railway (GTR) for Southern services.

Design

Class 170 on the left has a BSI 'Compact' coupler whereas Class 171 on the right has a Dellner coupler.

The Southern fleet is fitted with coupling devices (Dellner) different from other Turbostars, and is classified as Class 171 for this reason.^[2] The four-car units were built with the new couplers, but Class 170 two-car units were fitted at a later date, and reclassified as Class 171/7 after the modification. Three more two-car units were later acquired, but these were built from new with the new couplers.

Southern gained 170 392 from South West Trains. The coupler on this unit has also been changed to the Dellner type. The unit has been reclassified and renumbered from 170 392 to 171 730. This unit was first delivered carrying Southern livery and the number 170 727 (because SWT needed another 170 and it was cheaper to place another unit on the Southern order than place a new order). It never operated in this form and was transferred to South West Trains where it became 170 392.

In 2015, Southern gained 170 421 - 170 424 from First ScotRail. The coupler on this unit has also been changed to the Dellner type. The unit has been reclassified and renumbered from 170 421 to 171 921, 170 422 to 171 922, 170 423 to 171 923 and 170 424 to 171 924. This unit was came off lease following the transfer of the Scottish franchise to Abellio.

Seating

Class 171s have mainly standard-class seating plus either nine first-class seats on a two-car, 13 on a three-car or 18 on a four-car; all first-class seats are reclining and have mains power sockets adjacent to the seats.

Standard-class seating includes five full-size folding seats in the area by the universal toilet on the DMOCL(W) vehicle. With these seats folded there is room for wheelchair users and bicycles. Each passenger door vestibule area also has two flip-down seats.

	Standard Class				1st Class	TOTAL
	Normal	Full-Folding	Flip-Down	Total
DMOCL(W)	38	5	4	47	9	56
DMOCL	50	0	4	54	9	63
DMOSL	64	0	4	68	0	68
MOS	74	0	4	78	0	78
Class 171/7 (2-Car)	102	5	8	115	9	124
Class 171/8 (4-Car)	236	5	16	257	18	275
Class 171/9 (3-Car)	160	5	6	238	13	422

Operations

Southern (previously named South Central) acquired an initial fleet of six two-car Class 171/7 and six four-car Class 171/8 units, to replace its ageing Class 205 and Class 207 "Thumper" fleet.^[3]

The first units were introduced in 2003 on the Ashford to Hastings "Marshlink Line" (now running further to Brighton). Services on the Oxted to Uckfield 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-Brighton 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 6-car or 8-car trains.

Fleet details

Formation of 2-Car Class 171/7: DMOCL(W) + DMOSL
Formation of 4-Car Class 171/8: DMOCL(W) + MOS + MOS + DMOCL
Formation of 3-Car Class 171/9: DMOCL(W) + MOS + DMOSL

Class	Operator	Number built	Year built	Cars per set	Unit nos.
Class 171/7	Southern	10	2003–2004	2	171 721 - 171 730[4]
Class 171/8		6	2004	4	171 801 - 171 806[4]
Class 171/9		4	1999-2001	3	171 921 - 171 924[4]

References

1. Marsden, Colin J. (2007). Traction Recognition. Ian Allan Publishing. ISBN 978-0-7110-3277-4.
2. Class 171 - Welcome to the Southern E-Group Web Site. Retrieved 2011-05-01.
3. Class 170 2Page - Welcome to the Southern E-Group Web Site. Retrieved 2011-05-01.
4. http://www.thejunction.org.uk/flist_171.html The Junction Class 171 Fleet List