Эксперименттік екі кабиналы локомотивтің прототипі

Prototype dual cab steam locomotive

The Leader was a class of experimental steam locomotive, produced in the United Kingdom to the design of the innovative engineer Oliver Bulleid. The Leader was an attempt to extend the life of steam traction by eliminating many of the operational drawbacks associated with existing steam locomotives. It was intended as a replacement for the ageing fleet of M7 class tank engines still in operation on the Southern Railway (SR). Bulleid considered that attitudes towards the labour intensity of steam operation had changed during the post war period, favouring dieselisation and electrification. In an effort to demonstrate the continued potential of steam, Bulleid pushed forward the boundaries of steam power, hoping it could compete with diesel and electric locomotives in terms of labour saving and ease of operation. As the proposal progressed, Bulleid saw that certain tasks required with conventional steam locomotives could be eliminated by adopting some of the features of the contemporary Southern electric locomotives. By developing the proposal further, Bulleid settled for a design of bogie locomotive, which spread the weight more evenly over the rails and reduced the axle loading.

A series of initial ideas were presented to the Southern Railway management by Bulleid that incorporated double ended running, giving the locomotive driver maximum visibility in either direction without a boiler or tender obscuring his view. The need for a turntable to turn the locomotive was therefore eliminated, although the initial designs were rejected by the operating department because of problems with welding technique. The accepted design included two 0 6 0 steam bogies with weight saving sleeve valves and chains to couple the driving axles. The boiler was offset to provide space for a communication corridor, allowing the driver to access both cabs without leaving the locomotive, an arrangement which led to later problems. The firebox, near the centre of the locomotive, was fed by the fireman from a third cab, linked to both driving cabs by the communication corridor. The entire ensemble was placed on a common frame and thus often referred to as an , even though the actual notation is since both engine units pivoted as on a Garratt, Double Fairlie or Meyer locomotive. The Leader prototype was constructed at Brighton railway works, work beginning in 1946. The latter order was cancelled after the Southern Railway was taken into public ownership, to allow trials to be carried out on the prototype. The valve gear used the unusual sleeve valve arrangement that was also tested on the ex LB&SCR H1 class Hartland Point in parallel with the construction of the first Leader locomotive. The locomotive sat on the unusual Bulleid Firth Brown wheels, which were lighter, yet stronger, than the spoked equivalent. The use of sleeve valves and oil baths to lubricate the moving parts of the engine units was inspired by contemporary internal combustion engine practice. However, this resulted in an over complicated mechanism that was difficult to maintain, perpetuating the seizures it was meant to eradicate. This feature was removed from both bogies of the prototype as the trials progressed. Another innovative feature of the steam bogie assembly was the ability to interchange them when faults occurred, an easy operation for maintenance staff when compared to the complexities of overhauling a regular steam locomotive's motion. The Leader had a "dry lining" firebox. It was not surrounded on top and sides by a "jacket" of water as in normal practice, but was constructed of welded steel and used firebricks instead of water for insulation, a novel but troublesome solution. The firebox was not initially equipped with a firebrick arch, although one was retro fitted during the summer of 1950. The arch was problematic because it led to a tendency for flames to enter the cab at high outputs, a situation made worse by the narrowing of the firebox area. The problem lay with ash gathering around the edges of the slide, allowing air to leak into the smokebox, thereby reducing the overall efficiency of the locomotive. For ease of maintenance, the boiler, firebox and smokebox were encased in steel sheeting, which meant that the engine's shape resembled that of a modern diesel locomotive. That was a major departure from traditional steam locomotive design, allowing the engine to be cleaned using a carriage washing plant. The locomotive was designed to carry 4 tons (4.06 tonnes) of coal and of water, and the coal bunker was covered by a tarpaulin to prevent water ingress into the fireman's cab. Entry into the locomotive was by way of ladders leading up to sliding doors, although, due to the bogie design, the climb into the fireman's cab necessitated clambering over the oilbath casing. British Railways inherited the Leader project upon nationalisation in 1948, which was far enough advanced to continue constructing the prototype, as Bulleid was still Chief Mechanical Engineer of the newly formed Southern Region of British Railways. Although work on the other four locomotives stalled, the prototype Leader emerged from Brighton as locomotive No. 36001 in June 1949. The other four members of the initial order made by the Southern Railway, Nos. 36002–5, were at varying stages of construction by the end of the development period. No. 36002 was almost complete, No. 36003 was without its outer casing, and Nos. 36004–5 were little more than sets of frames, although most of their major components had been constructed at Eastleigh and Brighton and were stored ready for fitting. This was considerably lower than the contemporary WC/BB pacifics which were rated as class 7, and this meant that the Leader had to be able to have an axle loading that would allow it to operate over secondary routes and on branch lines where the double ended design would be of most benefit, something that was not likely with the weight inherent in the design. On completion, No. 36001 was immediately put into service trials using empty passenger carriage stock in the south east of England. However, the results of the trials as reported to British Railways headquarters at Marylebone were "conspicuous by the absence of praise" for the strengths of the Leader, namely the boiler, braking system and total adhesion provided by the two bogies. Several theories have been put forward regarding this state of affairs, the most plausible being that the more conservative members of the railway workforce at Brighton and the Railway Executive felt that the Leader was too revolutionary and were keen to maintain the status quo.

Following trials that lasted over a year, No. 36001 was shown to have several flaws, including heavy coal and water consumption, mechanical unreliability, untenable working conditions for both fireman and driver, loss of steam through the cylinder rings and uneven weight distribution on the bogies. After renewing the cylinder assembly, it was tested around Brighton and Eastleigh using an LNER Dynamometer car, where good running was experienced at high costs in fuel and effort on the part of the fireman. For a period of two weeks the Leader was tested against the performance of a U class locomotive These trials were interrupted by breakage of the crank axles, these being replaced by axles from 36002 only for these to break in turn at approximately the same mileage as the originals. A related problem was that despite being a tall locomotive, at 12 feet (4 m), the cab ceilings were relatively low. The cab at the smokebox end of the locomotive suffered from the same excessive heat as did the fireman's cab. To circumvent this problem the locomotive was used in reverse, as the rear cab was next to the water tank and coal chute and therefore away from the hot gases circulating inside the smokebox. Despite its problems, the locomotive displayed outstanding steaming characteristics and total traction from the two power bogies on its trial runs. When properly fired, the Leader was capable of keeping up with the schedules, even running ahead on occasions. However, operational difficulties were encountered when stopping for water not only did the locomotive use water at a rapid rate, requiring frequent stops but the all enclosed casing and the overall height of the locomotive meant that many of the water cranes were too low to feed directly into the water tank, thus requiring either an improvised arrangement of scoops and hoses or filling the tank from a standpipe and hose both options greatly extended the amount of time needed to take on water. These delays tended to lose any time advantages gained when the locomotive performed well and affected the published performance figures. Despite hauling test trains over the Central Section of the former Southern Railway, the Leader prototype was never used on a revenue earning service because of the risk of failure of the valve gear and the adverse publicity this would cause for British Railways.

When the project was under the auspices of the Southern Railway, No. 36001 would have been numbered CC101. Since the design has six driving axles, the numbering would have been CC101–CC105 for the initial batch, the final number being the locomotive identifier.

Operational livery was photographic grey with red and white lining. The British Railways "Cycling Lion" crest was also used though, after the works photograph, this was painted over without explanation.

Production of the Leader demonstrated the inherent unsuitability of encasing a steam boiler in an enclosed superstructure. The environment inside was highly unsuitable, the weight was prohibitive, and necessary maintenance such as boiler washouts could only be achieved by a major dismantling of the locomotive. R. G. Jarvis, who was placed in charge of the project after Bulleid's departure, insisted that the locomotive required an entire re design to solve the problems of the original concept. After the problems during the trials in 1950, in November of that year 36001 and the four other Leader locomotives then in various stages of assembly were all cut up for scrap. The numberplate for No. 36001 is in the National Railway Museum; a locomotive builder's plate intended for the locomotive, but never fitted in service, was auctioned for £1050 in 2008. The Leader was a bold attempt at pushing back the boundaries of contemporary steam locomotive design and, if successful, may have prolonged the life of steam on British Railways.