LMSR Explorer Class; An ATL Vignette

[scots region]

Hello All, this is the first piece of written work that I’ve shared on this site, 2016 was a really terrible year in terms of stress, writing has been a bit of a relief for me. So I’ve decided to share with you, it is rough and I have probably made a lot of mistakes, but I hope that you find something to enjoy here.

 

The London Midland and Scottish Railway's 6000 class 'Explorer' class Pacific were, prior to the introduction of the Princess Royal and the Coronation class 4-6-2, the principal express motive power on the west coast main line. The class had arisen from the need to increase train speeds and to replace ailing LNWR types run down during the Great War. In essence the Explorers were a rough compromise between the Midland and London and North Western Railway schools of thought. The Midland preferred a 'little and often' approach of small locomotive run on lightly loaded services, where as the LNWR tended to run their machine to a far harsher degree.

 

Therefore the new class would be powerful enough to operate across the totality of the WCML between London Euston and Glasgow Central and across the sections therein. The construction of the thirty strong class was overseen by J.R Billington, the former chief draughtsman of the Lancaster and Yorkshire Railway, and George Hughes, who had inherited the position of chief mechanical engineer (CME) for the new company. Hughes had as early as 1924 proposed a Pacific design utilising 4 cylinders and 6ft 9in driving wheels. The new locomotive would be largely based on Hughes efforts and would share many feature of the old design, such as a similar diameter boiler, driving wheels and firebox.

 

Given that the locomotive had been designed by the former CME of the Lancaster and Yorkshire Railway, with input from the Midland Railway, for operation across the former LNWR network, it was, in essence a 'design by committee' and it would show. In particular a key inference would come from the former Midland Railway CME Sir Henry Fowler who had lead a deputation to France and had received the impact of 'compounding', recycling spent or low pressure steam in conjunction with high pressure steam. The Midland had gained some experience with compounds from the '1000' class of 4-4-0s, as had the L&Y. The issue presented with compounding is the need to incorporate a large low-pressure cylinder or cylinders into the design. Due to the constrains presented by the British loading gauge the L.P cylinders, for there were to be two on the Pacific, would have to be placed inside the frames to the detriment of the steam passages.

 

Construction of the new design would finally begin in late 1926, by early 1927 the prototype was ready for testing, in addition to the new pacific an experimental 2-8-2 'mikado' type utilising the same boiler had been produced for use on the Toton to Brent coal services. From 1927 to 1930 the remaining twenty-nine Pacifics and three more Mikados would be produced. The appearance of the new machine was massive, the huge boiler, almost six feed in diameter, dominated the design, accentuated by the diminutive funnel and dome. From the front of No 6000 the high inclined cylinders pushed up the running plate in a steep step, rakishly raising it clear of the first driving wheel set and giving the appearance of a machine 'hunched forwards'. To the rear the cab was typically Lancastrian, and finally the diminutive six wheel tenders, in the Pacific's case carrying just 3500 gallons of water seemed wholly inadequate to feed a machine of this size.

 

Overall the 'Explorer' and their Mikado cousins, now know as the '6100 class' possessed a brutalist beauty, slab sides and harsh angles. One feature that astonished observers could be found in between the frames, where due to the huge diameter of the low pressure cylinders, almost 2ft each, the frame walls had to be accommodated to allow the cylinders to project slightly outward. As can be imagined this complex arrangement was to be the class's Achilles heel. However the LMSR now had a machine that was, on paper, powerful and looked the part for the role it was to serve.

 

It has long been debated by Rail historians in the 80+ years since the first '6000' turned a wheel whether the LMSR should have concentrated its efforts into a smaller and less complex machine. Perhaps even one that avoid the use of compounding all together. Indeed in 1924, the same year that Hughes laid out what was to become the 6000 class, Fowler had proposed a 3 - cylindered compound 4-6-0, along similar lines to the '1000 class'. But it was not to be. There was some experience with a large compound machine on the part of the Lancaster and Yorkshire and Hughes who had over seen the reconstruction of that Railway's fleet of 4-6-0s, the 'Dreadnought' class, one of which, no 10456, had been converted on similar line to the new Pacific and Mikado with inside cylinders of 22in diameter. In general this machine was a relatively successful working between Crewe and Carlisle, demonstrating a 26% saving in coal over similar types, though this went down to just 9% when compared with members of its own class.

 

The Pacifics could do better than this due to their higher boiler pressure; 240lbs to 10456's 180lbs, however as with the 4-6-0 the Pacific was only a touch more efficient than similarly conventional machines. The main problem was the of the '6000' to exploit compound expansion and the resulting thermal efficiency. A problem exacerbated by the locos conventional blast pipe which in turn restricted the steam output and lead to increased coal consumption. Further the limitations of the design became apparent with the undersized axle bearings and solid crankshafts presenting a bug-bear on maintenance. Still so long as standards were maintained these problems would prove peripheral, at least with regards to the Pacifics.

 

Why go to the expense of naming a class of Steam Locomotives? The United Kingdom is unique amongst nations in the practice of naming their locomotives, a tradition stretching all the way back to the Rainhill trials and George Stephensons 'Rocket'. Though not all rail companies and certainly not all on the west coast held to this tradition, the first express motive power on a brand new company was certainly cause for it. The decision to name the first of the class after the leader of the failed South Pole mission would inevitably lead to such a theme of honouring those who had pushed the boundaries of human knowledge, or died trying. It could be remarked that it was temptation to name the first machine after a man who had honoured both halves of this philosophy. Still it was only logical that in addition to explorers the name list would be expanded to include scientists, ships and even locations visited.

The first batch of the new Pacifics began work on the Royal Scot service from Euston to Glasgow Central and the Mid-day Scot. These services started in both Up and Down directions at 10AM and 1:30PM respectively, there was also the 'Night Scott' startling at 11:45PM from Euston. The longest service the Pacifics worked was the 'Royal Highlander' a service that began all the way in Inverness. However the Explorers could soon found on a variety of other services, in particular between Birmingham and Euston and even cross county turns. As mentioned before whilst the Pacifics were able to improve on the earlier efforts of the L&Y 4-6-0s and LNWR Claughtons, they continued to grapple with the problem of thermal efficiency and the limitations of the internal valve gear, in particular fatigue cracks occurring in the crank webs, necessitating full replacement in a very cramped space. All of which hampered reliability and availability. However the high speeds maintained in service could mollify the efficiency problem to some extent, with higher steam generation. The same could not be said of the Mikados.

 

The Midland Railway had made extensive use of double heading on its main line between the Toton coal fields and Brent, this practice was inherently limiting to both train lengths and speeds and a drain on availability due to the need to operate two locomotives with two crews. Therefore the Mikados were seen as the avenue by which the LMSR could affect a saving and an increase in capacity at the same time. However this increase would be limited by the need to accommodate the private owners, most coal wagons in the country at the time were privately owned and would remain so until the conclusion of hostilities in Europe. Therefore it was impossible to make such improvements such as continuous breaking, or even the LNER solution, which had been to offer an upgraded wood and steel panel wagon capable of carrying 16tons of coal apiece.

 

Thus with the Mikados confined to, at best 40 mph, the design defects became ever more pronounced. In fact speeds could be so low that the corresponding drop in compound expansion rate in effect meant that the '6100s' were being worked as conventional machines. The fact the LMSR's overtly complex replacement for a pair of conventional 3F/4F 0-6-0s was burning as much coal as the same was made all the more painful when an LNER Class P1 was trialled on the Toton-Brent section and ran rings around its counter part. Still, if anything, the abject failure of the Mikados helped spur the motive department in a far more positive direction, a newer and far simpler breed of eight wheelers would supersede the Mikados and one of the most unique machines on any British mainline to be constructed.

 

In January of 1932, William Stanier, the man who would define locomotive policy in the British Isles was appointed CME of the LMS, prior to which the LMSR had suffered a rather headless period after the retirement of both George Hughes and Henry Fowler. With the only new class of Locomotives added being the class 8 4-8-0s, constructed under the guidance of the temporary CME, at the time, the unfortunately named Ernest Lemon. However the new design proved to be reliable and free steaming and very effective. With the 8Fs replacing the failed Mikados Stanier pushed ahead with his plans for a new standard range of Locomotives, which would include the celebrated 'Princess Royal' and Class 'Black' 5 respectively. The Explorer's in the meantime continued on the top service, gradually being pushed on to secondary services and limited in their range by the new types. It was during the Stanier years though, that the Explorers would be changed the most, first receiving larger tenders with increased coal and water capacity and then large smoke deflectors to deal with drifting exhaust. Finally the biggest deficiency of the design would be tackled, the still troublesome internal cylinders.

 

It should be added that problems were also developing with the '6000' boiler, which due to the need to maintain inner water tube lengths of 17 feet, possessed a combustion chamber of no less than 4 feet. This was adjoined to the boiler by a tight circumferential riveted seam that stretched right around the inner firebox, due to expansion this was prone to cracking and difficult to repair. It was another weak spot in an already contentious design. Stanier would take action in 1935, opting to replace the Locomotives parallel boiler with a tapered boiler and to finally rid the Explorers of their compounding, the inner low pressure cylinders were replaced with conventional high pressure ones driving off internal walschaerts valve gear. The result was a far more economical machine that while not as powerful was much lighter and easier on maintenance. In time the whole class would be so treated, not though before a fresh global conflict tested the class.

 

The Second World War was a tremendous strain on the entirety of the British Rail network, as with most of the motive power stock the war saw the 'Explorers' do the hardest work as yet expected of the class. The unrebuilt examples suffered in particular from a decline in coal quality and the reduction in maintenance staff, in some cases the valve gear became completely seized. It would not be until 1956, well into the British Rail period, that the last Explorer would undergo rebuilding. By this time the class had long been pushed from the top services by the Stanier 4-6-2s and now the new 'Britannia' Pacifics and for the most of the decades after the war could be found on secondary services, usually between Birmingham and Euston. One service that stood out was a doubleheaded working from Birmingham to Glasgow worked, rather poignantly, by No 46000' and 46013'; 'Captain Robert Falcon Scott' and 'Lawrence Edward Grance Oats'. Soon BR would dispose of the entirety of its steam fleet and the 'Explorers', already largely superseded by more modern machines, were an early target for withdrawal. The first withdrawal took place in 1963 and by the mid 60s the whole class was gone.

Happily three examples survived into preservation era; the first of the class and prototype No 6000 was saved for the national collection and is today on display at York. No 6015 was saved by the LMS Pacific Locomotive Society and has been returned to steam twice since the 1980s. Finally 6025 'Sir Edmund Hillary' was saved in a joint effort by the British Mountaineering Council and has been placed on permanent display at the Birmingham science and technical museum.

 

The complete fleet list is presented bellow;

 

6000: Captain Robert Falcon Scott CVO

6001: Albert Borlase Armitage

6002: Sir Charles William Rawson

6003: Edward Adrian Wilson

6004: Sir Ernest Henry Shackleton

6005: George Francis Arthur Murlock

6006: John Robert Francis Wild

6007: Micheal Barne

6008: Louis Charles Bernacchi

6009: Reginald William Skelton

6010: Edgar Evans

6011: Edward Leicester Atkinson

6012: Henry Robertson Bowers

6013: Lawrence Edward Grance Oats

6014: Victor Lindsay Arbuthnot Campbell

6015: Charles Robert Darwin

6016: HMS Beagle

6017: David Livingstone

6018: Sir Henry Morton Stanley

6019: Captain James Cook

6020: HMS Endeavour

6021: Zackary Hicks

6022: Captain John Gore

6023: Sir Walter Raleigh

6024: Roanoak

6025: Croatoan/ Sir Edmund Hillary

6026: Sir Joseph Banks

6027: Sir George Leonard

6028: Captain Sir Richard Francis Burton

6029: John Hanning Speke

6030: Vice Admiral Sir Francis Drake

6031: Golden Hind

6032: John McDouall Stuart

6033: The Spring of Hope

6034: Christopher Columbus

 

A line drawing of the prototype '6000'

 

A painting of the first of the class at Crewe by Robin Barnes

 

Reference List 

Robin Barnes, Locomotives that never were, Some 20th century British projects, Jane's Publishing Company Limited (London) (1985) PG 44

E.S Cox, Locomotive Panorama. Vol 1, Ian Allen Ltd, Shepperton (1965) PG 39, 45, 54

Ian Sixsmith, The Book of the LM Garratts, Irwell Press Limited (2007) PG 1

[EddieB]

A very interesting account of two classes of locomotives that deserve wider attention.  It may be worth noting that the high axle loading of both (18 1/2 tons) tended to restrict their sphere of operation and meant that they were candidates for early withdrawal rather than being cascaded onto secondary-line services.

 

The relevant RCTS "red book" tells how names were allocated for the Mikados but never applied (allegedly at the behest of Josiah Stamp who regarded the naming of freight locomotives an unnecessary expense):

 

6070 Sir John Franklin

6071 James Clark Ross

6072 Mungo Park

6073 Edward Whymper

 

 

 

Why go to the expense of naming a class of Steam Locomotives? The United Kingdom is unique amongst nations in the practice of naming their locomotives, a tradition stretching all the way back to the Rainhill trials and George Stephensons 'Rocket'. Though not all rail companies and certainly not all on the west coast held to this tradition, the first express motive power on a brand new company was certainly cause for it. The decision to name the first of the class after the leader of the failed South Pole mission would inevitably lead to such a theme of honouring those who had pushed the boundaries of human knowledge, or died trying. It could be remarked that it was temptation to name the first machine after a man who had honoured both halves of this philosophy. Still it was only logical that in addition to explorers the name list would be expanded to include scientists, ships and even locations visited.

 

 

(To be serious, albeit briefly)  Naming of locomotives was far more common than that, especially in the early days and pre-dating the Liverpool & Manchester.  While most of the leading industrialised countries had tended to abandon the practice as their railways progressively coalesced and were nationalised, names nevertheless were sometimes applied - even through to classes of electrics and diesels.

[scots region]

Thanks for the feedback Eddie, it really feels good to have crafted this.