Built: 2015 – 2019
Manufacturer: Bombardier Transportation, Derby
Entered Service: 2019
Number in Service: 
30 x 4 car 25Kv AC units
18 x 4 car 25Kv AC/750v DC units
6 x 5 car 25Kv AC/750v DC units
Number of Carriages per Train: 4/5
Seats per Train: 189/241
Passenger Capacity: 678/855 (approx.)

---

Train Formation:  

4 Car: Driving Motor Standard – Pantograph Motor Standard – Motor Standard – Driving Motor Standard
5 Car: Driving Motor Standard – Motor Standard – Pantograph Motor Standard – Motor Standard – Driving Motor Standard

Train Length: 4 car: 271ft 11in 5 Car: 337ft 6in
Train Width: 9ft 2ins
Train Height: 12ft 5ins
Train Weight: 4 Car AC: 144 Tonnes, 4 Car DV: 151 Tones, 5 Car DV: 182 tonnes

---

Sub Classes

Class 710/1 – 25Kv AC – Operated on Lea Valley Lines & Romford to Upminster Line.
Class 710/2 – 25KV AC/750v DC – Operated on Gospel Oak to Barking and Watford DC Lines.
Class 710/3 – 25KV AC/750v DC – 5 Car Sets Operated on Watford DC Line.

Class 710 Electric Multiple Unit History

At the beginning of 2012, following two years in service, Transport for London realised that the Class 172 Diesel Multiple Units it had procured for service on London Overground‘s Gospel Oak to Barking Line were unable to handle the passenger demand placed on the line.

TfL issued a tender for the supply of eight three or four-car diesel trains, however this was shelved as the Government announced the electrification of the Gospel Oak to Barking Line in June 2013 and the proposal to operate the line with a fleet of electric multiple units.

With this new proposal, TfL saw an opportunity to modernise the remaining original members of its fleet, and therefore expressions of interest were invited for a total of 39 four-car electric multiple units, 30 for the Lea Valley Lines, 1 for the Romford to Upminster Line (to replace the Class 315/317 EMUS still in service) and 9 for the Gospel Oak to Barking services, replacing the Class 172 DMUs.

Subsequently, 6 five-car units were added to the tender to allow the five-car Class 378 Capitalstar EMUs on the Watford DC Lines to be returned to the North/East London Lines.

An invitation to Tender was issued by Transport for London in early 2015. July of that year saw an announcement from TfL that they had placed a £260million order with Bombardier Transportation for 45 four-car Class 710 Aventra Electric Multiple Units, with an option for a further 24 units and additional options for the supply of extra carriages to extend some units to five cars.

Beginning in April 2018, the delivery schedule for the new units began to slip, with further delays being announced in June of that year. Transport for London reported in November that they hoped the units would commence service in December however further delays, including in unit testing, prevented this.

Due to the lease on the existing Gospel Oak to Barking units becoming due in January 2019, and the need to transfer them to other lines, TfL temporarily deployed three Class 378 Capitalstar units to cover services on the line until the Class 710s became available.

In early May 2019, the Class 710 EMUs gained approval to enter passenger service from the Office of Rail and Road, with the first two units entering service on the Gospel Oak to Barking Line on 23 May, with the remaining six entering service in August.

The first unit for the Watford DC Lines entered service on the 9th September 2019 with the rest commencing service over the following months. Units on the Lea Valley Lines began running on the 3rd March 2020 and the Romford to Upminster Line on 5th October.