This photograph shows a first glimpse of new passenger trains on the Thameslink route.
First Capital Connect and the Department of Transport will unveil the new rolling stock at an exhibition next week.
The new trains will come into use on the Bedford to Brighton line - which includes Mill Hill Broadway and Hendon - in 2016.
Designed by manufacturer Siemens, 115 high capacity trains are being built as part of the Government-sponsored £6.5b Thameslink Programme.
It will be showcased at the ExCel Exhibition Centre, in London Docklands, on January 29 from 2pm to 8pm.