up to a total of 216. Maintenance arrangements were also included, involving the construction of a new depot near New Cross Gate station to perform heavy maintenance tasks upon this new fleet. The new fleet, designated Class 378, was manufactured by Bombardier at its facility in Derby. In July 2007, TfL announced it had ordered a further 36 Capitalstar carriages for £36 million. The order comprised three additional four-car units for the East London Line, and 24 additional carriages to extend the original 3-car units for the North London Line into 4-car units, to be delivered in 2011. On 16 September 2008, the first complete unit was unveiled and began testing on Bombardier's test track before being delivered for testing on the national network. On the first public unveiling of the Class 378, TfL announced that it had reached an agreement to procure a further three dual-voltage units, taking the total number to 57. These units were intended to enhance the fleet once the South London line was brought under London Overground's control. In February 2013, approval was gained for the procurement of 57 additional vehicles, allowing the whole Class 378 fleet to be lengthened from four to five cars for greater capacity. At the time, TfL's Business Plan called for five-car services to begin on the East London line from November 2014, while the rest of the electrified Overground network would follow by the end of 2015. In January 2016, TfL announced that all units were now in a five-car configuration. Design and features The Class 378 Capitalstar is a dual-voltage electric multiple-unit train (EMU), designed to be supplied via either the 750 V DC third rail or the overhead lines. It is a customised version of Bombardier's Electrostar family, aimed at the short-distance mass-transit end of the market. Following completion of five-car upgrades in 2016, each unit is formed of a driving motor vehicle and an intermediate motor vehicle either side of an intermediate trailer. In Class 378/2 units, the intermediate trailer carries the pantograph and electrical transformer. The interior of the train was designed to maximise passenger capacity. Traditional seating was eliminated and longitudal seats adopted instead, along with wide areas around the doors to speed the entrance and exit of passengers. Furthermore, a significant portion of each car is intended for use by standing passengers, and thus have grabrails and other holding points for such passengers