The Great Northern Railway (GNR) Class O2 was a class of three-cylinder 2-8-0 steam locomotives designed by Nigel Gresley for freight work and built by the GNR from 1921. Further examples were built by the London and North Eastern Railway (LNER) from 1924.

All 41 Group Standard O2s were classified as O2/3. In total, 67 O2s were built by the Great Northern Railway (GNR) and the LNER. In March 1939, the original eleven GNR O2s were rebuilt with lower cabs to fit the 13ft 0.5in loading gauge.

The following is a list of locomotives built for the Great Northern Railway. As is customary, engine classes are organized according to the man who was locomotive superintendent when the class was introduced, and to whom the design is often attributed. Six men held this post during the existence of the Great Northern Railway.

The Great Northern Railway (GNR) Class O2 was a class of three-cylinder 2-8-0 steam locomotives designed by Nigel Gresley for freight work and built by the GNR from 1921. Further examples were built by the London and North Eastern Railway (LNER) from 1924.

The GNR O2 was development of the O1, which initially differed almost only in the number and arrangement of the cylinders. Instead of the previous two cylinders, three smaller ones were now used to improve power transmission and smooth running.

After this rebuilding their first O2 boilers were ones built at Gorton and the only O2 boilers numbered in the Gorton Series with a G prefix. These engines were as follows, with boilers noted from their 1929 rebuilding.

The Great Northern Railway (GNR) Class O2 was a class of three-cylinder 2-8-0 steam locomotives designed by Nigel Gresley for freight work and built by the GNR from 1921. Further examples were built by the London and North Eastern Railway (LNER) from 1924.

The O2 locomotives were powerful three-cylinder heavy mineral engines with a 2-8-0 wheel arrangement. The first, a prototype, was completed in May 1918 by the Great Northern Railway (GNR). Production commenced in 1921 and the last appeared in …

No. 3841 was a class O2 2-8-0 steam locomotive that was built for the London, North Eastern Railway by Doncaster Works in 1942. BRDatabase.

Rebuilt to O2/1 with side-windowed cab. Retaining original GN-style cab. Number of locomotives logged in this class is 67. Number of locomotives with photos available in this class: 45.