# LNWR Jubilee Class

The London and North Western Railway (LNWR) Jubilee Class was a class of 4-4-0 4-cylinder compound locomotives by F.W. Webb. A total of forty were built from 1897–1900. Slightly unusually for the LNWR, the class received a number series, this being 1901–1940. All were named, mostly after Royal Navy battleships.

## Iron Duke and Black Prince

The first two of this class were prototypes, built to different designs to permit a comparison. The first, No. 1501 the Iron Duke (later re-named Diamond Jubilee and then Jubilee), was a 4-cylinder simple locomotive with 15 in × 24 in (381 mm × 610 mm) cylinders. The second, No. 1502 Black Prince, was not Webb's first compound, but was his first 4-cylinder compound and the first in the UK. The outside high-pressure cylinders were the same as Iron Duke's, the inside low-pressure cylinders were 19+1⁄2 in × 24 in (495 mm × 610 mm).
There was no simpling valve or other means for starting, and so when starting they just operated as small 2-cylinder simples. The Joy valve gear was shared between high and low pressure, with a rocking lever to the high-pressure valves. The inside cylinders were angled above the outside cylinders and although this could have been solved by cranking the rocking levers, this gave an uneven drive to the valves; valve-setting between both of them had to be a compromise position, ideal for neither, and so gave an uneven power distribution between high and low. Their running was thus not as free-running as it might have been, which Webb would address in his later designs.
These were also Webb's first designs with a leading bogie rather than a pony truck, which was also described as a "double radial truck". The truck pivots geometrically at a point behind its rear axle, although there is no single mechanical pivot point. This motion is controlled instead, like Webb's earlier single radial truck, by curved radial slides, with a radius of curvature at the centre of the truck of 10 ft 9 in (3.28 m).
Another novel feature was that both locomotives were fitted with double chimneys. The smokebox was partitioned internally into upper and lower halves, the lower section exhausting through the front chimney and the upper tubes through the rear chimney. The blastpipes were fed separately, the front chimney from the left cylinders and the rear from the right. After some time in service, the two chimneys were replaced with a single chimney on an undivided smokebox and their performance and fuel consumption measured again. It was found that the compound locomotive had identical performance both with and without the double chimney, but that the simple locomotive was improved by it. The double chimney was re-fitted to Jubilee, but the production locomotives were built as compounds without it.
After around a year's running, the simple had run for 33,517 miles, with an average coal consumption of 40.3 pounds per mile and the compound (starting slightly later) for 23,503 miles with a consumption of 38.1 pounds per mile. The compound was thus cheaper by 2.2 pounds per mile, or 5%.
The ratio between LP and HP cylinders was 1.69, lower than that considered optimal. Webb's 3-cylinder compounds had used the more usual figure of 2. To improve this to 1.87, Webb had decided to increase the size of the LP cylinders to 20+1⁄2 in × 24 in (521 mm × 610 mm), and this was applied to the production locomotives.

## Service

As with other Webb compounds, they were mechanically unreliable. As a result, George Whale rebuilt these as two-cylinder simple locomotives of the Renown Class, starting with 1918 Renown in 1908. Rebuilt engines retained their numbers. Rebuilding continued so that at the grouping of 1923, only 9 Jubilees remained, being 1903/4/8/11/12/15/23/27/29.
1908 Royal George was withdrawn in January 1923, but the remaining eight were allocated the LMS numbers 5110–5117, in sequence. Two, 1904 Rob Roy and 1923 Agamemnon were withdrawn 1923, without receiving new numbers. The LMS rebuilt the remaining six into Renowns in 1924, making the class extinct (Their subsequent history is discussed at LNWR Renown Class).
A successor to this class, the Alfred the Great class, retained the 4-cylinder compound design but used two sets of valvegear, both Joy, allowing the LP cutoff to be controlled independently.

## Locomotive list

LNWR Jubilee class locomotive list :
| LNWR No. | LNWR name | Crewe Works No. | Date built | Date rebuilt | LMS No. | Date withdrawn | Notes |
| 1901 | Jubilee | 3856 | Jun 1897 | Apr 1919 | 5156 | | Named Iron Duke until December 1897, numbered 1501 until March 1899 |
| 1902 | Black Prince | 3857 | Jun 1897 | Aug 1919 | 5157 | | Numbered 1502 until March 1899 |
| 1903 | Iron Duke | 3928 | Mar 1899 | May 1924 | 5110 | | |
| 1904 | Rob Roy | 3929 | Mar 1899 | — | (5111) | May 1923 | Never carried its LMS number |
| 1905 | Black Diamond | 3930 | Mar 1899 | Aug 1914 | 5137 | | |
| 1906 | Robin Hood | 3931 | Apr 1899 | May 1917 | 5149 | | |
| 1907 | Black Watch | 3932 | Apr 1899 | Feb 1922 | 5178 | | |
| 1908 | Royal George | 3933 | Apr 1899 | — | — | Jan 1923 | |
| 1909 | Crusader | 3934 | Apr 1899 | Nov 1919 | 5159 | | |
| 1910 | Cavalier | 3935 | Apr 1899 | Aug 1921 | 5172 | | |
| 1911 | Centurion | 3936 | Jun 1899 | Dec 1924 | 5112 | | |
| 1912 | Colossus | 3937 | Jun 1899 | May 1924 | 5113 | | |
| 1913 | Canopus | 3938 | Jun 1899 | Mar 1910 | 5132 | | |
| 1914 | Invincible | 3939 | Jun 1899 | Sep 1916 | 5144 | | Renumbered 1257 in April 1920 |
| 1915 | Implacable | 3940 | Jun 1899 | Nov 1923 | 5114 | | |
| 1916 | Irresistible | 3941 | Jul 1899 | Feb 1919 | 5155 | | |
| 1917 | Inflexible | 3942 | Jul 1899 | Aug 1922 | 5184 | | |
| 1918 | Renown | 3943 | Jul 1899 | Jun 1908 | 5131 | | |
| 1919 | Resolution | 3944 | Aug 1899 | Nov 1919 | 5160 | | |
| 1920 | Flying Fox | 3945 | Aug 1899 | Dec 1920 | 5166 | | |
| 1921 | John of Gaunt | 3995 | Feb 1900 | Apr 1913 | 5134 | | Named T. H. Ismay until April 1913 |
| 1922 | Intrepid | 3996 | Feb 1900 | Oct 1916 | 5146 | | |
| 1923 | Agamemnon | 3997 | Mar 1900 | — | (5115) | | Never carried its LMS number |
| 1924 | Powerful | 3998 | Mar 1900 | Jun 1922 | 5183 | | |
| 1925 | Warrior | 3999 | Mar 1900 | Apr 1917 | 5147 | | |
| 1926 | La France | 4000 | Mar 1900 | Mar 1922 | 5180 | | Shown at Exposition Universelle in Paris |
| 1927 | Goliath | 4001 | Mar 1900 | Jan 1924 | 5116 | | |
| 1928 | Glatton | 4002 | Apr 1900 | Aug 1921 | 5173 | | |
| 1929 | Polyphemus | 4003 | Apr 1900 | Feb 1924 | 5117 | | |
| 1930 | Ramillies | 4004 | Apr 1900 | Apr 1916 | 5142 | | |
| 1931 | Agincourt | 4045 | Sep 1900 | Dec 1921 | 5176 | | |
| 1932 | Anson | 4046 | Sep 1900 | Jun 1920 | 5162 | | |
| 1933 | Barfleur | 4047 | Sep 1900 | Apr 1921 | 5169 | | |
| 1934 | Blenheim | 4048 | Sep 1900 | Sep 1920 | 5165 | | |
| 1935 | Collingwood | 4049 | Oct 1900 | Mar 1910 | 5133 | | |
| 1936 | Royal Sovereign | 4050 | Oct 1900 | Jun 1917 | 5150 | | |
| 1937 | Superb | 4051 | Oct 1900 | Jan 1919 | 5154 | | |
| 1938 | Sultan | 4052 | Oct 1900 | Feb 1920 | 5161 | | |
| 1939 | Temeraire | 4053 | Oct 1900 | Aug 1919 | 5158 | | |
| 1940 | Trafalgar | 4054 | Oct 1900 | Apr 1921 | 5170 | | |