The name Juniper designates three types of EMUs which are part of the Coradia family. The class 334 consists of 40 three-car sets built for Scotrail for use under 25 kV AC via overhead line. The class 458 consists of 36 four-car sets built for South Western Railway for use under 750 V DC third rail. The most remarkable type was the class 460, built as eight-car trains for the Gatwick Express. Their special nosecones earned them the nickname “Darth Vader”. Starting in 2013, SWR rebuilt its fleet of class 458 sets together with the class 460 into 30 five-car class 458/5 sets.

The designations “Electrostar” and “Capitalstar” stand for a family of electric multiple units built by Adtranz, later Bombardier, for several British companies. They share some similarities with the Turbostar family of diesel multiple units. In most Electrostar sets, all cars except one have two traction motors in one bogie with 200 to 300 kW. Depending on the class, they are equipped for service under 750 V DC via third rail, 25 kV AC via overhead line or both. More than 600 sets have been built since 1999.

The classes 357 and 379 are built for AC service and have a top speed of 100 mph. The classes 375 and 377 have the same top speed, but can operate under AC and DC. The class 376 is a DC-only variant that only reaches 75 mph. The fastest one in the family is the class 387 that is capable of AC and DC operation and reaches a top speed of 110 mph. The class 378 is the only one that carries its own name “Capitalstar”. It was built for the London Overground and can also operate under AC and DC with a top speed of 75 mph. For better acceleration, it has three traction motors in four of its five cars.

The British classes 220, 221 and 222 designate diesel-electric multiple units which were built by Bombardier and reach a top speed of 125 mph or 201 km/h. Independent of the length of the sets, each car has a 750 hp Cummins QSK19 providing power to the inner axle of each bogie. They became notorious when trains running over the Dawlish Seawall in south Devon during storms were stopped by software shutdowns. These were caused by the effect of salt water spaying over the roof-mounted brake resistor grids.

The class 220 is called “Voyager” and is made up of four cars. In 2000 and 2001, 34 sets were built. The main change of the class 221 “Super Voyager” is the tilting mechanism, what can be recognized by the outside-frame bogies instead of the inside-frame bogies of the 220. These 44 sets built in 2001 and 2002 can consist of four or five cars. Both classes can be run in multiple with each other.

The class 222 carries the name “Meridian”. It doesn't have a tilting mechanism and also has the inside-frame bogies seen on the 220. Between 2003 and 2005, 27 sets were built with either four or nine cars each. They were later configured to five and seven cars. Although they were already replaced by trains like the class 810 on some lines, they still have a future due to the many non-electrified lines in Britain.

In 1997, North Western Trains ordered 27 diesel multiple units from Alstom for longer distances. These class 175 trains together with the class 180 make up the “Coradia 1000” family and were built in Great Britain. The eleven two-car trains form the class 175/0 and the 16 three-car trains form the class 175/1. A part of them was originally intended to be built for 125 mph, but in the end all were only ordered for 100 mph. After being used for an extended period by Arriva Trains Wales, the operator is Transport for Wales Rail since 2021. They are to be replaced by the CAF-built class 197 in 2023.

The class 180 is a diesel multiple unit related to the class 175, together forming the Coradia 1000 family. They were ordered by First Great Western and are five-car trains capable of 125 mph (201 km/h), consisting of four second class and one first class coaches. Each coach has a 750 hp Cummins QSK19 engine that powers both axles of one bogie via a Voith three-stage hydraulic transmission. 

All 14 sets are owned by leasing company Angel Trains. Due to problems with the transmission, FGW returned them to Angel Trains. After the problems had been solved, they came to several operators, also FGW operated some again later. Today four sets are in storage and all other ten are being operated by Grand Central.

Following the privatization of British Railways, Virgin Rail was given the InterCity West Coast franchise, which includes some lines between London and Edinburgh/Glasgow along the West Coast Main Line. Above all, the class 87 and 90 electric locomotives and the older passenger cars were to be replaced. For this purpose, a fast multiple unit was to be developed, which, thanks to tilting technology, should allow higher running speeds in cueves with a high level of passenger comfort at the same time.

The tilting technology comes from Fiat Ferroviaria and allows an inclination of up to eight degrees. In contrast to older systems, it is no longer hydraulic but electromechanical and thus saves maintenance costs. The pantographs are also tilted so that they are always in the correct position in relation to the catenary. The “Tilt Authorization and Speed Supervision” (TASS) system monitors the use of the tilting technology and the permitted speed. Trackside beacons transmit information to the train, for example to suppress tilting in narrow underpasses.

The majority of the trains' engineering comes from Fiat, but final assembly took place at Alstom's Washwood Heath facility. The trains were delivered consisting of eight cars each, but were soon expanded to include another car. The car bodies were mainly made of aluminum, with nose sections made of composite materials, which were nevertheless able to meet the crash standards of the time. A lot of work was put into the design to achieve a visually appealing, aerodynamic shape.

In seven of the nine cars, the inner axle of both bogies is powered. The traction motors are suspended under the frame and transmit their power via a cardan shaft. Although the trains are designed for 140 mph (225 km/h), they could only be approved for 125 mph (201 km/h). This is because the West Coast Main Line could not be upgraded as planned and thus the signaling does not allow for higher speeds.

Between 2001 and 2004 initially 53 sets were completed. Problems that arose caused the decommissioning of the classes 87 and 90 to be delayed. Soon the trains were setting new records on the 401 mile long WCML between London-Euston and Glasgow. The distance southbound was covered in 3 hours and 55 minutes and northbound in two minutes less. Meanwhile, on the non-electrified North Wales Coast Line, they were hauled by a class 57 diesel locomotive. A train was destroyed in a derailment at Grayrigg in 2007 where only one person died due to the structure.

From 2010, a total of 31 trains were lengthened to eleven carriages and then referred to as class 390/1. At the same time, four more were built in Italy, each consisting of eleven cars. When Avanti took over InterCity West in 2019, the Pendolinos went to Avanti West Coast. The trains are being modernized since 2021. A first-class car is exchanged for a second-class one and the interior is modernized and equipped with power sockets.

Under the name “Turbostar”, Bombardier (originally Adtranz) combined four classes of diesel multiple units that were based on the classes 165/166 “Networker Turbo”. Production took place at the Adtranz/Bombardier factory in Derby. They were the first new vehicles purchased by British railway companies after privatization, with Chiltern Railways as the first customer.

They are designed to be coupled with the “Sprinters” of classes 150 to 159. However, with a top speed of 100 mph (161 km/h), they are faster over longer distances. Compared to their predecessors, they are also largely constructed of aluminum, but have more powerful engines from MTU.

The different variants each consist of two to four cars. The first delivered Class 168 is also called “Clubman”. Classes 170 and 171 only differ in the couplers. The class 172 has bigger differences, as it has more powerful engines and a mechanical six-speed gearbox instead of the two-stage hydraulic Voith gearbox. In the subclasses 172/2 and 172/3 there are additional gangways on the fronts.

When Arriva planned to order new multiple units for the Northern Trains franchise, CAF from Spain was selected since these managed to offer both diesel and electric trains on the same platform. So the class 195 was ordered as the diesel variant and the class 331 as electric variant. The class 195 is being powered by one 390 kW MTU engine per car that was assembled by Rolls-Royce. Each engine transmits its power to both axles of one bogie via a ZF hydromechanical gearbox. This allows a top speed of 160 km/h or 99 mph. 

In total, Northern operates 25 two-car sets and 33 three-car sets, of which the first ones were delivered in 2019. West Midland Trains ordered a variant with gangways at the ends that was designated class 196. The order included twelve two-car sets and 14 four-car sets. The third and largest operator is Transport for Wales Rail with 51 two-car and 26 three car sets. These are designated class 197 and also have gangways, but only 375 kW per engine. In the near future, TfW may order more sets from CAF for additional lines.

When Arriva UK was looking for new trains for the Northern franchise, they selected CAF since they were the only manufactuer that could deliver electric and diesel trains on the same platform. The electric variant of the Civity became class 331, while the diesel variant is class 195. In contrast to Civity variants in other countries, the British trains do not use Jacobs bogies. They ordered 31 three-car units and twelve four-car units which have a top speed of 100 mph and eight 220 kW traction motors. 

At the same time, FirstGroup ordered twelve five-car class 397 units for the TransPennine Express. These have a more streamlined design and a top speed of 125 mph. TPE calls these trains “Nova 2”. The third electric Civity variant that will be introduced in the UK will be the class 897. These are three-mode trains which can run under 25 kV AC, on battery and with diesel. Each set will consist of ten cars and have a top speed of 125 mph. Ten have been ordered for entry into service in 2028 and they will be called “Serenza”.

The A-Train is a large family of trainsets with electric power transmission that is being used in multiple countries. One thing in common for all models of the family is that their bodies are constructed from double skin aluminium extruded sections, which are friction stir welded. The type AT300 designates a number of classes used for intercity and long-distance services in the UK.

The first was the class 395 “Javelin” ordered by Southeastern for the High Speed 1. They have an operational top speed of 140 mph (225 km/h) and also have the French safety systems KVB and TVM-430. Depending on section, they are either operating under DC with the British safety systems at a top speed of 100 mph or under AC with the French safety systems at their full speed.

For intercity traffic with 125 mph (201 km/h), a programme called “Hitachi Super Express” was launched in 2009. This led to the classes 800 to 803, 805, 807 and 810 of which the first ones were built in 2014. They are operating under brands like “Azuma”, “Nova”, “Paragon”, “Evero” and “Aurora”. All of them can operate under 25 kV AC and some are bi-mode trains with powerful MTU power packs. The latest one, the class 810 “Aurora” that is currently being introduced by East Midlands Railway, forms a five-car set that delivers nearly 4,000 hp in diesel mode from four power packs and nearly 5,400 hp in AC mode.