Rolling stock manufacturer Bombardier Transportation has announced that it has received a formal order to supply new trains for the London Overground Gospel Oak to Barking Line (link below.)
http://www.transportbriefing.co.uk/story.php?id=4685

The £33m order is for 12 2-car diesel multiple units. Unlike the recent London Overground electric train orders for the North and East London Railway, which will see Transport for London own the new trains, rolling stock leasing company Angel Trains will buy this latest batch of trains. Angel is expected to lease eight to London Overground Rail Operations Ltd, which runs Overground trains for TfL, with the remainder being made available to Chiltern Railways. Laing Rail, which owns Chiltern and was recently sold to German state rail operator Deutsche Bahn, owns 50% of LOROL.

By having a leasing arrangement, the trains can be transferred relatively easily to another operator if the line is electrified in the future.

Bombardier says the new trains will be delivered between the fourth quarter of 2009 and the third quarter of 2010.