The Great Central Railway Class 11F or Improved Director Class is a class of 4-4-0 steam locomotive designed by John G. Robinson for passenger work. The LNER classified them as Class D11 from 1923. They were based on the earlier GCR Class 11E "Director" class (LNER D10). There were two subclasses: D11/1 were the original GCR engines and D11/2 were those built in 1924 by the LNER to a reduced loading gauge with smaller boiler mountings for hauling passenger trains in Scotland.

The 11F Class was initially used on passenger work on the GCR system, including fast expresses from Sheffield Victoria to London Marylebone. Later in their careers, they were used on short-distance passenger trains. On lines of the Cheshire Lines Committee during the late 1940s and early 1950s, they hauled expresses between Manchester Central and Liverpool Central, also semi-fast trains from Manchester Central via Northwich to Chester Northgate.

Their 6 ft 9 inches driving wheels made them fast locos, but consequently unsuitable for hauling freight trains. The eleven original 11F locos were withdrawn during 1959 and 1960 as diesel multiple units took over operation of the shorter distance passenger trains, the remaining 24 lasted only a couple more years. Of the 35 built, one has been preserved as part of the national collection.