The type, which was entirely manufactured in Japan, is the first Hitachi-built rail vehicle to be sold to a European customer,[11][12] as well as being the first British order for a Japanese train.

Following the completion of 4,000 miles (6,400 km) fault-free running six months ahead of schedule, a 'preview' service was launched between London St Pancras and Ashford via Ebbsfleet on 18 June 2009.

[8][21][22][23] During June 2005, a contract valued at £250 million was signed with Hitachi Europe to supply 28 units, with Eversholt Rail Group acting as the financier (ROSCO); at this point, the new fleet had an expected service date of 2009.

[29] The contract was also the first British order for a Japanese train; as such, Hitachi viewed the deal as a key opportunity to establish itself in the UK market.

[34] Maintenance services are provided via a consortium, referred to as 'DEPCO', which included HSBC Rail (finance), Fitzpatrick Contractors Ltd (construction), RPS Burks Green (architects/civil engineers), EMCOR UK (mechanical and electrical plant) and GrantRail (trackwork) constructed a new maintenance depot building at Ashford and the updating of the existing depot site.

[39] The facility included a five-track trainshed with bogie drop made by BBM and train lifting equipment from Mechan.

Other facilities included carriage washing plant, a 25 kV OHL test track, and sidings for rolling stock.

[37] The design and layout of the depot, which was optimised specifically for the Class 395, enables the most efficient workflow possible, including minimal complex shunting actions, physical minimisation wherever reasonable, and in line with modern data management practices.

[45] Days later, it was unveiled by Secretary of State for Transport Ruth Kelly at a media event held at Hitachi's new Ashford maintenance facility.

[52] The performance metric of 4,000 miles (6,400 km) fault-free running was achieved six months ahead of schedule, clearing the way for a 'preview' service to be offered between London St Pancras and Ashford via Ebbsfleet.

[6] The preview service allowed for further train testing under real-world conditions,[53] during which the type reportedly achieved a 99% punctuality rate in the first month of operations.

[58][59] Even during the preview service, the Class 395 presented several performance improvements in comparison to conventional rolling stock, including its high rate of acceleration, lower noise levels (primarily attributed to its air conditioning arrangements), and its aesthetic appeal.

Railway journalist Richard Clinnick observed several minor shortcomings of the interior, such as the somewhat cramped seating arrangement and the lack of securing straps at the baby changing facility, but positively reviewed the overall package.

[6] In September 2010, it was reported that several passengers were concerned by the presence of a 'wobbling' motion that occurred within some tunnel sections; the phenomenon was described by Southeastern as non-dangerous, but all trains were fitted with dampers that prevent any recurrence of the issue.

[75] Unlike the steel-bodied 400 Series, the Class 395 has its carbody (walls, roof, floor) formed from friction stir welded (FSW) double-walled hollow extruded aluminium body panels, a technology that Hitachi Rail considers to be a part of its A-Train train family specification.

[8][76] The manufacturer claims that the FSW approach achieves minimal strain while providing a lightweight and high strength carbody in comparison to conventional techniques.

[76][77] The propulsion system of the Class 395 comprises 16 electric motors each rated to produce 210 kW (280 hp) that work in conjunction with four IGBT converter/inverter units.

[88] A mockup Class 395 unit was named after athlete Dame Kelly Holmes; the name was subsequently transferred to an operational unit and 11 other "fast Britons" – Jamie Staff, Steve Backley, Sir Steve Redgrave, Rebecca Adlington, Sir Chris Hoy, Ben Ainslie, Daley Thompson, Duncan Goodhew, Katherine Grainger, Lord Sebastian Coe, and Dame Tanni Grey-Thompson; all Olympic/Paralympic medallists – were selected in a public vote.

The selected names were Alistair Brownlee, Ed Clancy, Hannah Cockroft, Jessica Ennis, Mo Farah, Jason Kenny, Jonnie Peacock, Victoria Pendleton, Ellie Simmonds, Dame Sarah Storey, Laura Trott, and David Weir.

[17] In 2009 Hornby Railways launched two model versions of the BR Class 395, a super detailed model, and a basic representation of the prototype as part of their Railroad range both in South Eastern Blue livery and in 2012 Hornby released a special Olympic Games Livery in both super detail and basic in OO gauge.