The Holmes G7 (NBR Class P) 0-4-4T Locomotives
Although Holmes' tenure at the North British Railway (NBR) represented a large increase in locomotives, the twelve Class P (LNER G7) locomotives were the only passenger tank locomotives which he designed. These closely resembled Drummond's G8 design which the NBR built in 1877. A total of twelve G7s were built in two batches, six in 1886, and six in 1889.
Between 1911 and 1913, the G7s were rebuilt by Reid with new boilers of a similar design but with combination injectors replacing the older non-lifting type. This new boiler design was also fitted to the J33s at the same time.
Originally, the G7s worked local services out of Glasgow. Later in NBR ownership they would become distributed further afield to such places as Carlisle, Dunfermline, and Dundee. After Grouping (1923), the G7s would continue to work local passenger services, although further movements including Jedburgh, Bo'ness, and Grangemouth would occur.
Six of the G7s were withdrawn between 1926 and 1927, and the remaining six were withdrawn between 1930 and 1932.
Technical Details
| Cylinders (x2): | 17x24in. | |
| Motion: | Stephenson | Slide Valves |
| Boiler: | Diameter (max): | 4ft 5in |
| Length: | 10ft 1in | |
| Heating Surface: | Total: | 1059 sq.ft. |
| Firebox: | 100 sq.ft. | |
| Tubes: | 959 sq.ft. (202x 1.75in dia.) | |
| Grate Area: | 17 sq.ft. | |
| Wheels: | Coupled: | 5ft 9in |
| Trailing: | 3ft 6in | |
| Tractive Effort (85%): | 12,817lb | |
| Length: | 34ft 2.5in | |
| Total Wheelbase: | 22ft 3in | |
| Coal Capacity: | 2 tons 4cwt | |
| Water Capacity: | 1281 gallons |
Preservation
None of the G7s survived into preservation.
Models
An etched nickel silver 4mm kit of the G7 is available from 52F Models.
An etched brass 7mm (O scale) kit is available from 62C Models.