Passengers numbers have grown by more than 160% since Transport for London took over the under-performing Silverlink service in 2007.
The service is consistently one of the UK’s best performing rail services and scores highly on passenger satisfaction league tables thanks to its modern trains and visible staffing.
The carriages will be built by Bombardier Trains in Derby and will allow the network’s existing trains to be increased from four to five carriages.
Today’s £88m order forms part of a previously announced £300m package to boost capacity, which will also see platforms extended to cope with the new, longer trains.
Confirming the order, Mayor of London, Boris Johnson, said: “London Overground has been a truly dazzling success and more and more Londoners are now using the vastly improved service.
“Not only will these new carriages help us meet passenger demand, but they will also support jobs and growth at their birthplace in Derby.”
