The Class 172 is a planned diesel multiple unit (DMU) of the Turbostar family similar to the Class 168, Class 170 and Class 171.

Technical details and variants

There will be four sub-types:

• Class 172/0 - two-car units to be operated by London Overground
• Class 172/1 - two-car units to be operated by Chiltern Railways
• Class 172/2 - two-car units to be operated by London Midland
• Class 172/3 - three-car units to be operated by London Midland

The 172/0s and 172/1s will resemble the existing Turbostar trains in not having end gangways and will have a top speed of due to their use on the high volume/short distance services, such as those on the on the Gospel Oak to Barking Line. The Class 172s used by London Midland will resemble the Class 375 and Class 377 Electrostars by having end gangways to allow access between units. These trains will have a maximum speed of . The Class 172 trains will be lighter than other Turbostars thanks to the addition of similar lightweight bogies to those fitted to the Class 220 Voyager trains.

Differences from Class 150

A Class 172 will have fewer seats than a Class 150 it replaces (e.g. a three-car 150/1 has 35 more seats than a three-car 172/3) but greater overall capacity due to the increased room for standing passengers as well as wider aisles intended to speed boarding and alighting and reduce waiting time in stations. The trains will be air conditioned and have no openable windows, unlike Class 150 units.

Operators

London Midland will operate a total of 27 two-car and three-car units. The Class 172s will replace the Class 150 Sprinter trains currently in use on services to and from Birmingham Snow Hill by end of July 2010.

London Overground will be using two-car Class 172s to replace the Class 150s on the Gospel Oak to Barking Line from February 2010. Eight units will be leased by London Overground Rail Operations Ltd (LOROL), the London Overground concession operator, from a rolling-stock leasing company (ROSCO) rather than them being purchased directly by Transport for London.

Chiltern Railways will obtain four two-car units in the same order as that of London Overground to supplement the current Class 165 Networker Turbos on their routes from London Marylebone (particularly the Aylesbury line), which will be delivered from late 2010. These trains will differ from the London Overground units through the addition of ATP and Tripcock safety systems to make them compatible with the rest of the Chiltern fleet.

In late 2007 and early 2008, orders were placed with Bombardier by two rolling stock leasing companies (ROSCOs) to purchase a number of Class 172 Turbostars. In December 2007, Porterbrook ordered 15 three-car and 12 two-car units for London Midland for delivery in 2010. In January 2008, Angel Trains, on behalf of London Overground and Chiltern Railways, ordered 12 two-car units for delivery, which would have been delivered during 2009. However, difficulties encountered by Bombardier over the deliveries by its suppliers led to delays in filling the Class 377 and Class 378 orders, with subsequent knock-on delays for building the Class 172s. work was due to begin by the end of 2009 through the freeing up of one of Bombardier's production lines following the completion of the Class 377 order for First Capital Connect.

Fleet details

Class	Operator	Number built	Year built	Cars per set
Class 172/0	London Overground	8	2010	2
Class 172/1	Chiltern Railways	4
Class 172/2	London Midland	12
Class 172/3		15		3

Further potential orders

As part of their franchise agreement, London Midland have an option to purchase an additional 26 Class 172 vehicles which could potentially allow further cascade of their existing rolling stock.

In 2008, First Great Western applied to the Department for Transport to re-equip its Cardiff to Portsmouth via Bristol services with 11 new four car DMUs which would potentially allow the existing Class 158s to be cascaded to other services. According to the West of England Partnership, these are likely to be "similar to Class 170s", suggesting that they might be Class 172s.

The Government announced in December 2008 that Bombardier, with its Turbostar design, was one of the pre-qualified bidders (along with CSR of China, CAF of Spain and Rotem of South Korea) for the first 200 DMU vehicles of its planned 1300 new carriages. These new trains were intended for use on suburban and inter-urban services operated by First Great Western, First TransPennine Express and Northern Rail. However, with the announcement of the electrification of the Great Western Main Line, the DMU order was cancelled, with the needs of the TOCs planned to be met by cascades of existing stock.

References