GER Class M15
The GER Class M15 was a class of 160 steam locomotives designed by Thomas William Worsdell and built for the Great Eastern Railway between 1884 and 1909. The original class of locomotives were fitted with Joy valve gear which was notoriously difficult to 'set'. This earned them the nickname of 'Gobblers' thanks to their high coal consumption rates. As a result, between 1911 and 1920, 32 of them were rebuilt by James Holden with Stephenson valve gear and higher pressure boilers. Despite this, the nickname stuck for many years after.
Rebuilding
Rebuilding included the fitting of a higher pressure boiler, and also involved replacing Joy valve gear with Stephenson valve gear thus forming the M15R class.Modifications
Many were fitted with condensing gear for working in the London area. In 1949 seven F5s were fitted with vacuum-controlled regulators, converted from Westinghouse air brake to steam brake, and fitted with push-pull apparatus and trip cock gear for branch line operation.. Five of these locomotives worked trains on the line between Epping and Ongar, two were allocated to Yarmouth for working the Yarmouth-Beccles line. 67218 would later be transferred to Epping in 1955. These seven received British Railway lined-black passenger livery; the rest were unlined-black.Ownership
London and North Eastern Railway
One-hundred-and-eighteen M15s and all thirty-two M15rs, passed into London and North Eastern Railway ownership at the 1923 grouping. The number 7000 was added to the ex-GER fleet. They received the following classifications:- Unrebuilt locomotives: F4.
- Rebuilt locomotives: F5.
- Numbers 7789 and 7790 were incorrectly classified F6. British Railways reclassified both of them F5 on 22 December 1948.
| Location | F4 | F5 | F6 |
| Cambridge | 1 | - | - |
| Colchester | 2 | 1 | - |
| Ipswich | 1 | 2 | - |
| Lowestoft | 2 | - | - |
| Norwich | 2 | - | - |
| Parkeston | 1 | - | - |
| Stratford | 109 | 27 | 2 |
| Totals | 118 | 30 | 2 |
During World War 2 in 1940 a number of the class were taken out of service and had armoured plating added. They were then deployed on armoured trains, not only in their native East Anglia, but in Kent, Lincolnshire and as far north as Aberdeen. They were also found at Ministry of Defence depots in the west of the country (Bicester, Long Marston and Wooton Dassett. By 1943 they were being returned to the LNER and were later fitted with brass plaques commemorating their role. These read - "LNER - during the war of 1939-1945 this locomotive was armoured and hauled defence trains on coast lines".
British Railways
Thirty-seven F4s and all of the F5s, including 7218 and 7219, passed into British Railways ownership in 1948. Their BR numbers were:- Class F4: 67151-67187..
- Class F5: 67188-67219
Withdrawal