[3] The collapse of Railtrack following the Hatfield accident further delayed this upgrade work, and the new stock did not enter squadron service until 2003.

Bodyside power doors are electrically operated, a move away from the air-powered systems of previous generation EMUs.

These trains change to third-rail DC supply on a dual-voltage section of the West London line north of Shepherd's Bush.

[7] Since March 2009, dual-voltage Class 377 units operated some Thameslink Bedford to Brighton, Rochester and Ashford services (see below).

The first of these, unit 377501, was delivered to Cauldwell depot on 27 February 2009 after making its first appearance through the Thameslink Central London core.

The loss of these units until September 2009 was covered by the temporary cascade of a number of Class 350/1s to Southern from London Midland, which operated services between East Croydon and Milton Keynes.

], as specified in Department for Transport documents, published in September 2013, relating to the new combined Thameslink, Southern and Great Northern Franchise.

[15] Porterbrook is funding the £55 million five-year Project Aurora programme to refurbish 214 Class 377 Electrostars operated on Southern services.

[17] Changes include the installation of screens showing live GTR and London Underground service information, the provision of USB and power points, energy-saving LED lighting and a passenger-counting system which will enable GTR to analyse how busy individual services are.

[23] The 8 sets were built as 5 car units with dual voltage configuration, costing circa £60 million in total, and they were delivered during 2014 for service entry in December of that year.

On 28 November 2016, a fire broke out in the MOSL car of a Southern Class 377 (unit 377442) at Eastbourne station, causing damage to the ceiling and interior.