Interior view of a D78 District Line carriage

The new D78-stock trains were introduced on the District line in 1980. They were the first trains on the line specially designed for One Person Operation. A key feature of the new stock was the Passenger-operated doors, which removed the need for a guard. However, many Passengers expressed reservations about this and door operation later reverted to the driver. This picture shows the interior of a D78 carriage. The seats have been upholstered in a distinctive orange, yellow, brown and black moquette design. Only District line trains used this design. New D-stock trains were introduced between 1980 and 1983, when 75 trains replaced the older District line stock.