In April 2007, as part of the Route Utilisation Strategy for the Brighton Main Line, it was announced that Southern would procure an additional 48 Class 377 carriages to replace an identical number of carriages (12 x 4-car units) due to be transferred to First Capital Connect. Eleven further dual-voltage units were then added to the order, making a total of 23. The units were commissioned at Southern's Selhurst depot in Croydon before being transferred to First Capital Connect's Bedford Cauldwell depot. 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 377/5s operated mainly on Bedford to Brighton services but in the peaks formed part of FCC's and Southeastern's joint service to places such as Rochester and Ashford.