|Power Classification||1P reclassified Op in 1953|
|Introduced||1889 – 1895|
|Weight||46t 18cwt – IoW locomotives 48T 8cwt|
|Driving Wheels||4ft 10ins|
|Cylinders||Inside – 17.5in x 24in|
|Valve Gear||Stephenson (slide valve)|
Adams was presented with the problem of a greatly increasing volume of commuter traffic experienced with the suburbanisation of London during the 1880s. This was exacerbated by the fact that there were few locomotive classes in the London and South Western Railway (LSWR) stable that could undertake commuter traffic at the desired level of efficiency. The LSWR therefore required a locomotive with attributes of power and compactness, with a small wheel size to gain acceleration on intensive timetables. Adams settled upon the 0-4-4T wheel arrangement to provide the basis of what was to become the O2 Class.
The second of William Adam’s 0-4-4 designs, the O2 Class was a smaller version of his previous T1 class of 1888.
|T1 class introduced in 1888|
The brief behind the design was to create a locomotive capable of mixed-traffic operations, a characteristic dictated by the relatively small wheel diameter and smaller cylinders, effectively to replace the obsolete Beattie Well Tank (0298 class) on branch line work and general shunting duties. As a result, a compact locomotive with high route availability was produced, a factor that would be essential during the later career of the class.
|0298 Beattie Well Tank introduced in 1874|
Production began in 1889, with the first 20 being constructed at the LSWR’s Nine Elms works. The success of the locomotive ensured that a second batch of 30 locomotives was ordered the next year. A final batch of ten was constructed by 1895.
The sixty locomotives built were originally numbered 177 – 236 by the LSWR and these numbers were retained by the Southern Railway for the mainland locomotives. After nationalisation in 1948 they were renumbered by the addition of 30000 to their existing Southern Railway numbers to give a new number in the 30177 to 30236 sequence.
Some of the locomotives were fitted with Drummond type boilers with Ross pop safety valves on the top of the dome. This was not in general found to be an improvement and many retained the original Adams boilers.
The class was initially used intensively on London suburban services, but began to be replaced on these as early as 1897 by the introduction of the more powerful Drummond M7 and T1 classes. As a result the O2s were cascaded to lighter services, and became distributed throughout the LSWR system, being of particular use on restricted branch lines due to their relatively low weight and short wheelbase.
Some locomotives were fitted for working push-pull services in the period 1931-1933 but two of these had it removed in 1949 and 1956.
All of the O2s survived to be taken into Southern Railway ownership after the Grouping in 1923. They continued to be used across the former LSWR network, however, electrification and the introduction of more modern types started to make them redundant. This allowed the Southern Railway to send the first 2 spare examples across to the Isle of Wight. Other redundant mainland locomotives were withdrawn, with eight going in the 1930s, and four more in the 1940s. Until the 1930s some of them could always be seen marshalling carriage stock in Clapham Junction sidings.
Despite the early withdrawals, a number of O2s lasted well into BR days, working various branch lines until closure began to take place in the late 1950s and early 1960s. As a result, the mainland O2s became redundant and the last to go was number 30225 in 1962.
The class was mostly associated with the Isle of Wight railway system, with the Isle of Wight Central Railway making enquires as to the possibility of purchasing some class members in the early twentieth century. This plan, however, fell through, and it was not until after Grouping in 1923, that the newly formed Southern Railway was forced to resolve the desperate locomotive power situation on the Isle of Wight.
The opportunity to resolve this problem presented itself when electrification of the LSWR’s suburban network meant a cascade of newer, more powerful designs such as the M7s and T1s into the O2’s rural strongholds. As a result, several O2s became surplus to mainland requirements. Two of these spare engines were modified at Eastleigh works, with the addition of a Westinghouse Air Brake to allow compatibility with the Isle of Wight coaching stock. These two O2s were shipped across the Solent in 1923 and trialled extensively on services across the island, but particularly the intensive Ryde-Ventnor line services, where they proved to be highly successful. Further engines were then shipped across in small batches throughout the 1920s and 1930s.
The final two O2s were sent over in 1949, after Nationalisation, resulting in a total of 23 locomotives on the island. Due to tunnel restrictions at Ventnor, none of the final series of 10 with the higher cab roofs were sent to the island. Because of their compact nature, they proved ideal for island duties, although the problem of the lack of adequate coal bunker space hampered the class. This meant that from 1932, a much larger extended bunker was fitted to W19 (formerly 206), and this design subsequently became the standard for all the island locomotives. Locomotives on the Isle of Wight were renumbered in a separate sequence with the prefix W and taking the next available number, or the number of the withdrawn locomotive they were sent over to replace. Eventually those on the island occupied the entire sequence between W14 and W36. All the O2s allocated to the Isle of Wight were named after places on the island. The Isle of Wight’s unique numbering system was retained on the BR examples on the island, along with the names.
After the withdrawal of the last LB&SCR E1 class in 1960, the O2 became the single locomotive class on the island. They survived in service until the end of steam services on the Island, with an O2 operating the final train on 31 December 1966.
Two, numbers W24 Calbourne and W31 Chale were retained to work engineering trains during the electrification of the surviving Ryde to Sandown line. Both were withdrawn on completion of the electrification project in March 1967 by which time there was interest in preserving them. The attempt to preserve W31 failed, and it was scrapped in 1967.