The Class 387 is a planned type of EMU in the United Kingdom being constructed by Bombardier Transportation for the future Thameslink, Southern and Great Northern (TSGN) franchise. These trains will be part of the Electrostar family and delivery of these units is expected in 2015. They have been ordered to allow to be cascaded to other routes. In addition, an extra 140 carriages could be ordered. These trains will then be replaced by trains.