Railway World Volume 32
Number 377 (October)
London electrification goes ahead. 430-1
Initial announcement of Great Northern electrification to Royston, via main line and Hertford Loop, including dual voltage link to Moorgate via Drayton Park. Also mentions possible new high level terminal at King's Cross to accommodate airport traffic from Foulness: anyone for Boris?
Trevor Bailey. The oddest things strike me.
Undergraduate days in lazy, late 1930s Cambridge where the author (presumably the man better known as a cricketer), Alan Pegler and Jo Lever enjoyed themselves travelling by train for the joy of it. Enjoyed breakfasts on the northbound North Country Continental, fast A4-hauled journeys to King's Coss on the regular excursions: No. 4902 Seagull achieved 87 mile/h through New Southgate on one trip and ran from Welwyn Garden City to King's Cross in a fraction over 20 minutes. They used the LMS dmu to reach the East Coast route to watch the LNER streamliners, but enjoyed some amazingly fast steam train rides when a 2-6-4T and two coaches had to substitute. They also wandered round East Anglia on rover tickets and just missed a gate fine when they deliberately saught the wreck of the 11.02 ex-Hunstanton at Hilgay.
S.C. Townroe. More light on the Leader class. 436-8.
Mention of the Leader class locomotive, the last to be built under Southern Railway auspices just before nationalisation, arouses among steam locomotive enthusiasts visions of a revolutionary machine which could have kept the diesel locomotive at bay for many years. That such hopes were a long way from fulfilment has not been made clear, from the limited information so far published; instead there has grown up a belief in some quarters that the project was prematurely scrapped by a nationalised body without any attempt to persevere with the problems of a radically new design.
In fact, as will be explained in this article, there arose in the course of the trials of the one and only Leader class to be constructed and tested, No 36001, an impasse over excessive weight, which proved impossible to resolve. In passing, other examples come to mind of original steam locomotives (for example, the Paget and Ljüngstrom machines) which were brilliantly conceived but which ended in disappointment for one reason or another.
The story began in 1946. The Southern Railway had reviewed its post-war motive power requirements and the operating authorities put forward a request for tank locomotives for working passenger traffic on secondary routes and branch lines. The intention was to replace a variety of small tank locomotives, almost all of which were of Victorian or Edwardian vintage, by such types as the BR classes 3 and 4 tanks which were later to be produced under nationalisation The SR Chief Mechanical Engineer at that time, O.V.S. Bulleid, decided that the proposition could be taken a good deal further, by having a type of large tank locomotive which would be capable of working both main line and lesser trains through to destinations on secondary routes. To this end, the locomotive would be double-ended, to avoid the need for turntables. It would be mounted on two six-wheeled power bogiesan 0-6-6-0 or C-C in today's parlanceall wheels driven and braked, giving adhesion for working unbraked freight trains as well as passenger trains. The power bogie was to have all its parts working enclosed in oil baths and would be like an electric motor-coach, interchangeable, and requiring no attention outside main workshops.
A single underframe 65ft long carried the boiler, smoke-box, bunker for four tons of coal, tank for 4,000 gallons of water, a driving cab at each end and a fireman's cab in the space between the boiler and the bunker. A corridor was provided on one side. The boiler was of locomotive pattern except that the side and back water spaces of the conventional firebox were replaced by plain sheet steel lined with refractory material; four thermic syphons joined the crown of the firebox to the underside of the barrel. The object was to avoid the maintenance associated with stayed firebox water spaces, but the experiment was to prove a real hot-spot in more ways than one. Boiler pressure was 280 psi.
Each bogie carried three cylinders 12-!in diameter by 15in stroke. Valve gear, a smaller version of the Bulleid- Walschaerts gear as fitted to his Pacifies, operated sleeve valves with separate admission and exhaust ports. The wheels were 5ft lin in diameter. The centre axle was a three-throw crank and carried a chain sprocket at each end, outside the wheels. The outer and inner axles were plain, each with a sprocket at opposite ends, so that chains re- placed conventional coupling rods, one on each side of the bogie. This unsymmetrical drive must have added to the stresses in the three-throw crank, supported in two end bearings, whereby failures occured after running a low mileage.
The maximum permitted axle load on secondary lines was 19t tons, to which the West Country class conformed; if the Leader was to have the required route availability, the total weight in working order would have to be kept down to 112-!- tons (or 90 tons without coal or water). A con- ventional tank locomotive of equivalent power and weight could be taken as a 4-6-4 but by comparison the Leader design carried a superstructure with three cabs, six cylinders and six sets of valve gear, brake equipment for twelve wheels and 4,000 gallons (nearly 18 tons) of water-an exceptional quantity for a tank locomotive.
The calculated tractive effort was 26,350Ib, which would have placed it within the BR power classification 5 and thus hardly capable of main-line loads and schedules. The West Country class was rated as 7. With a fleet of 150 Pacifies (MN, WC and BB classes) the Southern did not need more main-line passenger locomotives. Hence, unless the Leader class could be made light enough to work on secondary routes and some branch lines, there was really no urgent need for it. To its courageous designer, however, the combination of so many new features, most of them potentially successful in theory, was evidently so alluring that the locomotive simply had to be built to prove itself. No calculated or actual weight figures were officially pub- lished.
The use of sleeve valves enabled the designer to have three cylinders en bloc between the bogie frames. Sleeve valves had proved satisfactory on stationary steam engines but they required special attention to lubrication; they were liable to distort at high temperatures, and to keep them steam- tight in the cylinder between the ports each valve on the Leader had 36 rings. To tryout the sleeve valves former LBSC Class HI Atlantic No 32039 Hart/and Point was fitted with them and during 1948 worked stock trains bet- ween Eastleigh and Lancing Works. Each sleeve valve had an extension through the front cover attached to a canted die-block which gave the sleeve a slight axial rotation at each stroke; this mechanism suffered breakages. No 32039's 3,500 gallon tender was insufficient for the 50 mile trips, thus indicating very high water consumption, and there was considerable steam leakage caused by broken rings.
Whether rings broke in service or were broken in the difficult process of assembly, with so many, was not established, but it was clear that much more development was needed to make this type of valve, new to locomotive use, a workable proposition for this particular application. Nevertheless, no time was available for prolonged experiments for No 36001 was already under construction at Brighton Works. No doubt Bulleid felt that the trouble with the sleeves was a matter of workmanship, or materials, which would be solved. The first trial runs took place in the Brighton area during 1949, but by June 1950 No 36001 had proved far from serviceable and was transferred to Eastleigh Works where, it was hoped, the staff would have more success with it. At the same time the ex-North Eastern dynamometer car and testing crew were sent from York to Eastleigh mpd to observe trial running on the main line between Eastleigh and Woking. The intention was to test No 36001 on an empty train, during the first fortnight of July 1950 and to take similar records, for comparison, with Maunsell U class 2-6-0 No 31618 during the second fortnight.
No one was anxious to drive or fire No 36001, which had earned the nickname of "The Chinese Laundry" from the heat and humidity inside it. The heat, radiated from the boiler and smokebox, and from internal steam pipes, made the interior only bearable by running with plenty of ventila- tion; even so, the temperature in the fireman's compartment was recorded as 120 deg F. The fireman had a window on one side only; he could not see, or be seen, by the driver. If a gauge-glass burst or a steam joint failed, the consequencies for the fireman might have been more serious than on a normal footplate.
The Locomen's staff representatives were not at all happy about the conditions under which No 36001 would have to be operated, and made it clear that, while they would not prevent one volunteer crew from working the trials, they would call for drastic alterations before the locomotive entered service. It has since been suggested that oil firing would have made things more congenial for the fireman; certainly, he would have been freed from the exertion of firing but he would still have had to operate the boiler controls in solitary confinement.
On trials, No 36001 did not maintain steam pressure with 10 coaches on the 1 in 250 gradient from Eastleigh to Basingstoke. Shortage of steam was aggravated by portions of the firebox lining becoming detached, allowing the steel firebox sides to become red hot. The refractory lining had to be increased in thickness and by so doing the grate area was reduced, with further detriment to steaming. The dynamometer car staff were unable to obtain any useful records because at no time did the locomotive run consis- tently over a distance. The trials were interrupted also by breakage of the 9in diameter crank axles; they were replaced by axles made for No 36002 but the latter broke after about the same mileage as the first set.
While No 36001 was in workshops for crank axle attention and for other lesser defects, the opportunity was taken to place it on the weighbridge. This revealed a disparity in wheel weights between one side and the other, and to effect a balance the corridor (the lighter) side had to be ballasted with cast iron weights. When the locomotive was weighed in this condition, it was obviously far in excess of the heaviest permitted axle-load, and further development, which held no prospect of weight reduction but rather the reverse, was pointless. In November 1950 the project was terminated, and in due course No 36001 and the other four Leaders in various stages of completion were cut up for scrap.
Even assuming that in due course all the purely mechanical teething troubles could have been overcome, and the total weight reduced, the principle of enslosing a large boiler within a superstructure was unsound; it made the living quarters for the enginemen intolerable; it involved within these quarters all the dirty operations of boiler washouts, smokebox cleaning, tube cleaning, repairs and examinations. The latter could not have been carried out properly without dismantling large parts of the superstructure. It may be some consolation to reflect that the steam locomotive was dying anyway, not for lack of progressive improvement but because it was replaced by forms of traction affording superior performance accompanied by more congenial conditions for the human element. No official announcement was made about the choice of eminent persons whose names were to be conferred on the Leaders. It was understood that the first would be Winston Churchill, with name plates to be removed from Battle of Britain class, No 34051, already bearing his name, and the second would be Field Marshal Montgomery. As always, the workshop wags had plenty of suggestions, including Fred Karno, W. Heath Robinsan, Roland Emmett (with due respect to the latter two gentlemen there was nothing personal in this, merely that the Leader locomotives seemed to share certain features of their designs), and other less worthy titles! Illustrations:photograph from author's collection shows members of the Institution of Mechanical Engineers grouped in front of No 36001 during their visit to Eastleigh in 1950; Leader class No 36001 passes Eastleigh South box with empty stock in August, 1950. Assistant Works Manager Clifford at the open cab window is getting as far away as he can from the torrid interior of the locomotive. first (and only) Leader runs trials with a dynamometer car in September 1950. In this view it is on the up main line at Allbrook. Eastleigh.
bell has tolled, and No 36001 is being dismantled in Eastleigh Works. This rare view is taken from the smoke box end, showing the boiler, side corridor with ballast and firebox. The fireman's compartment with its single side window is beyond, between the bunker and water tank.(all S.C. Townroe)
L.G. Marshall. Journey to the Himalayas1.
Darjeeling Himalayan Railway
M. Dunnett. Three Durham wagonways. 454-6.
South Hetton wagonway; Bowes Railway and the Pelaw Main wagonway.