Halls of Fame – A Mixed Traffic Masterpiece

Standard

Some might say, that the Great Western Railway’s “Hall” and “Modified Hall” class 4-6-0s were simply a do anything, go anywhere mixed traffic design – which they were – but of course, the GWR would not be able to operate without them. These locomotives were the unsung heroes of the steam railway, and yet not one was set aside for inclusion in the UK’s “National Collection”. Happily though a number of both the original Hall and Modified Hall designs can still be seen in operation, and under restoration. In fact, one of their number is being ‘re-modified’ to represent the precursor Churchward “Saint Class”, which is a tribute to the design’s longevity and importance.

This class of 4-6-0 was easily the most numerous on the GWR., and was a design whose ancestry can be directly traced to the famous Saint Class. In a number of instances they have been referred to as “6ft 0ins Saints”. No fewer than 258 of Collett’s new Hall Class engines were built between 1928 and 1943, following the highly successful modification and operation of saint class engine No. 2925 “Saint Martin”.

Designs for the new Hall Class locomotives were born out of Churchward’s practice, with some influence from the operating department.
They were perhaps the first truly mixed traffic type owned and operated by the GWR and although built when C.B. Collett was Chief Mechanical Engineer, the basic format had already been outlined by Churchward in his scheme of 1901. The success of the 43XX moguls would, in the opinion of’ the running department, be improved still further with the lengthening of the wheelbase and the provision of a leading bogie, and for greater power, a GWR Standard No. 1 boiler.

In December 1924, came off Swindon Works with 6ft 0ins coupled wheels, and the Collett side window cab. But, these were 
the most obvious differences, with others that were thought necessary on the rebuild but not included later, or modified for the production series engines.

The rebuilding of’ “Saint Martin” incorporated standard ‘Saint Class’ cylinders, which following conventional Swindon practice, required them to be carried lower in the frames, in order to line up with the centre line of the smaller coupled wheels.

Saint Martin - Green Folder GWR 63

This is the locomotive which gave birth to the most numerous, popular, and successful of’ the GWR two-cylinder classes. The extensive modifications to No.2925 Saint Martin, here seen in converted form, resulted in the building of the Hall Class 4-6-0s.    © Lens of Sutton

So, that’s where the new “Hall Class” started life, as a combination of an earlier 4-6-0 design, paired with the operating ideas and experience with the 2-6-0 “43XX Class” moguls.

The New Kid On The Block

The appearance of’ the new mixed traffic engines was not without its troubles, despite the successful trials with the rebuilt “Saint Martin”, though fortunately, none of these related to the design, construction, 
or operation of the new engines. On the GWR, as on other companies’ lines,
 the 1930s was a time when many of the older designs were being scrapped and replaced with more modern, more efficient designs. However, the rail enthusiasts of that time regretted the arrival of the “Hall Class” only because many of the ageing 4-4-0s – some dating back to 1890s – would soon be extinct.

The first 80 of the new breed of locomotives came out of Swindon Works under Lot 254, between December 1928 and February 1930.

4901 Adderley Hall copy

The first of the many – No. 4901 in photographic grey at Swindon Works in 1928. This was a very successful design, and formed the backbone of GWR and BR Western Region mixed traffic working until it was scrapped in 1960.           (c) Historical Railway Images

Unsurprisingly they were fitted with the Swindon Standard No.1 boiler, as adopted for all large 10-wheeled locos, and fitted to their predecessor “Saint Class” 4-6-0s, but with Collett now in charge, the footplate crew were provided with a larger, side window cab. On the face of it this might not seem a key design improvement, but compare the Hall cab to an older design, such as the Saints, with their Churchward cab, the protection from the elements was visibly improved.

In construction, the new design largely kept to Swindon practices, whether it was for boiler, firebox, frames, or bogie design, with the Collett changes having been proven in practice with the highly successful “Saint Martin” – rebuilt and delivered in December 1924. In fact this rebuild was so successful that an order for those first 80 “Hall Class” was placed with Swindon Works in December 1927.

Eventually, 257 of the “Hall Class” were built up until the early spring of 1943, and cost £4,375 each  in the first batch, and whilst subsequently, cost rose, they rapidly became the GWR’s workhorse, and universally operated across the network.

Hall diagram

Boiler, Frames, Wheels and Motion

These were the Swindon “Standard No.1”, and were fitted to all the GWR’s 10-wheeled locos, and were the same as those fitted to the “Saint Class”, but the Halls boilers had the added suffix ‘A’, as prescribed in the company’s extensive classification scheme. The boilers were built in two rings, with the second ring tapered, attached at the rear to a trapezoidal shaped firebox, following ‘Belpaire’ style, and “waisted in” to fit between the frames at the cab end. The firegrate itself had a flat rear portion, with the front tapering downwards, from just in front of the training coupled axle.

The cylinders were mounted on the outside of the frames, as part of a casting with half of the smokebox saddle. The inside admission piston valves were carried above the cylinders, and a rocking shaft transferred the movement through the frames from an extension rod, expansion link, and the eccentric rods attached to the driving axle. Sounds complicated! Eccentrics mounted on the driving axle were the characteristics of the Stephenson valve gear, which, by the 1920s was standard Swindon practice.

The 6ft 0ins coupled wheels had 20 spokes, and were paired with 3ft 0ins diameter wheels on the leading bogie. Churchward’s simple design principles in the generously proportioned axleboxes, with pressed in whitemetal liners were maintained by Collett – for the Hall Class these were 10ins long and 8 ¾ ins in diameter. Coupled wheels were balanced in pairs, with steel plates rivetted to the spokes, and molten lead poured into the gap, and was a change from earlier practice, and claimed to provide greater accuracy in balancing.

That same simple design approach was equally effective in the coupling rods, which were plain, or slab sided, with no fluting – a practice adopted on many railways, ostensibly to save weight and reduce hammer blow.

Tenders

No less than three different designs of tender were paired with the class. From No. 4901 to 4942, a standard Churchward 3,500 gallon design was used, whilst from 4943 to 4957, a new Collett design of 3,500 gallon capacity was used, and finally a new 4,000 gallon Collett tender for the rest. This last type still carried the characteristic out turn to the upper sides of the bunker space, but when Hawksworth took over from 1941, this changed, and with the new ‘Modified Hall’ and ‘County’ class 4-6-0s, a simple, slab sided tender was adopted. That old simplicity rule appearing again.

Hall Class – Leading Dimensions

Hall Class Dimensions

Hawksworth’s Modified Hall

This was a fair bit more than modifications, and demanded changes to jigs, tools and working practices at Swindon, and so perhaps to describe this as a modification was wrong. It was much more of a development, by applying Hawksworth’s ideas to Churchward design and building a new mixed traffic locomotive for the GWR.

Hawksworth too over from C.B. Collett in 1941, and oversaw the motive power of the GWR until nationalisation in 1948. But, where Collett had largely continued the Churchward model, Hawksworth took a more radical – with a small ‘r’ – approach. He had up until that point been the company’s Chief Draughtsman, with responsibility for locomotive testing.

First out of the blocks was the 6959 Class or “Modified Hall”. These 71 locomotives were built between 1944 and 1950, and based on the Hall Class, a number of experimental ideas included that improved the performance of the 6ft 4-6-0s across its operational range.

Modified Hall 7923 Green Folder GWR 69

Classic Modified Hall on shed in the early 1960s. No. 7923 “Speke Hall”, in final BR lined green livery and sporting the post 1956 on the Collett 4,000 gallon tender. On the fireman’s side, the Modified Halls had the fire iron tunnel alongside the firebox, as standard practice, whilst for 7923, the old familiar Collett 4,000 gallon tender was used.         Photo: RP Bradley Collection.

A key change in the design of the Standard No.1 boiler used on these engines, was the fitting of a 3-row superheater, with 21 flues, which was intended to improve the speed and performance of the type, along with further boiler/firebox changes to cope with poorer quality coal. Mechanically too, the Modified Halls were a simpler construction, with full length frames, and cylinders attached to the outside faces, instead of the previous casting, which included a part of the smokebox saddle. These changes inevitably brought down building costs, and the simpler layout reduced operating and maintenance costs.

The adoption of a single mainframe construction, from drag box to buffer beam demanded a major change to the fabrication, and assembly, of the cylinders and valves. This simple change away from part plate and part bar frame to all plate frame was a radical step, and which must have caused major changes in the practices used in the works foundry and erecting shops. The cylinders, still driving the Stephenson valve motion by means of rocking shaft, were also still 18 ½ ins by 30ins, but were now cast as two separate pieces, bolted to the outer, machines faces of the mainframes. To carry the smokebox, a new cross stretcher was placed between the frames, and extended upwards to provide a support and mounting for the smokebox itself.

Modified Hall diagram

All GWR two-cylinder engines had a pronounced fore and aft motion, especially when starting, and the Modified Hall was no different, and whilst their were inconsistencies in the layout of the steam and exhaust pipes at the front, that pronounced motion continued. But, perhaps the most obvious departure was the widescale adoption of mechanical lubrication. Up to the arrival of these locomotives, GWR practice was “hydrostatic lubrication”, which consisted of the driver counting the number of drops (15 drops every 2 minutes) of oil passing through a sight glass on the footplate. The new locomotives had the mechanical lubricators mounted on the running boards, just ahead of the leading coupled wheels, and for guidance, the cab gauges included an ‘oil’ / ‘no oil’ indicator.

The tenders on the first 14 of the modified class were straightforward Collett 4,000 gallon types, but from 6974 onwards, Hawksworth provided the new, much simpler to build, slab sided design. The approach here followed that of other railway companies, in pursuing a simpler design and build process, to reduce capital and operational costs, with the intent that maintenance practices would be cheaper.

Modified Hall Class – Leading Dimensions

Modified Hall Dimensions

Oil Burners

The use of fuel oil for railway locomotives at the time the Hall Class arrived was not in regular use in Britain, because of the abundance of coal supplies – and no doubt the cheap cost of mining.   Even so, it had been tried back in 1893, with the most famous examples being on the Great Eastern Railway – as an experiment.

Shortly after the end of World War 2, there was a coal shortage GWR, and in particular in 1946/47, where the severe winter drove increased demand. But, of course, there was a manpower shortage as well, despite the ‘Bevin Boys’, who were recruited to replace the young miners, who had been conscripted during the early war years.

So, the railways, including the GWR, revisited the idea of equipping steam locomotives for burning fuel oil. This was also encouraged by the promised removal of the fuel-oil tax, and in October 1946 a subsidy of £1 per ton was paid to consumers – such as a railway – of fuel oil. This subsidy offset the fuel-oil tax, and with that in mind the GWR planned to convert 84 Hall Class engines to oil burning, but in the end only 11 were completed, with another 10 fitted with the oil burning equipment. In addition, the Government promised help to all companies changing over from coal to oil, which included the bulk purchase of all the necessary equipment, both on the loco and on the shed.

Converted

Garth Hall - oil -Green Folder GWR 57

“Garth Hall” as converted to oil burning in 1946.

So, for the GWR, the first loco to be converted was No. 5955 “Garth Hall” in June 1946, and it was allocated a new number – 3950. The remaining 10 locomotives were converted in April and May 1947, and included: 4907/48/68/71/72, 5976/86, 6949/53/57. The average life of these locos as oil burners, was around 2 years, with all being reconverted to oil-burning in 1950.

Oil Refuelling Depot layout cover

Re-Converted

Garth Hall - no oil -Green Folder GWR 133

By 1950, the few Hall class engines that had been running as oil-burners, were all converted back to coal burning. In this view, the original candidate “Garth Hall” is paired with a standard Hawksworth 4,000 gallon tender.

Operations

So, why were these locomotives needed? They were introduced at a time when the GWR had few modern mixed traffic designs, but plenty of the express passenger variety, and whilst Churchward’s application of new developments, especially following French practices were a great improvement on the Dean era, traffic was changing. Churchward had already introduced the 47XX series of heavy freight 2-8-0s, but a design that could be used on both passenger – long distance, or shorter – and a variety of freight workings was becoming an essential tool in railway operations.

When the Halls started to appear, all of the ‘Big Four’ companies were engaged on modernising and standardising their locomotive stock, which, in the 1930s resulted in many hundreds of the old ‘pre-grouping’ designs being scrapped, and replaced by engines with a wider operational range.

On the GWR, Churchward’s approach to locomotive design and standardisation in 1901 was mirrored in later years, by British Railways from 1948, and included elements of current best practice at home and abroad. Tapered boilers for example were introduced after studying the American approach, whilst the firebox was developed from a design popularised in Belgium, by Belpaire.

Churchward’s successor C.B. Collett applied these radical changes introduced a decade or so earlier in the “Saint Class” conversion in 1924, and delivered the most successful mixed traffic design the GWR operated, as the “Hall Class” 4-6-0.

The earlier ‘standard designs’ had included a mixed traffic loco with 5ft 8ins coupled wheels, and was a type that had been advocated by the Operating Department. The Hall experiment – which you could conclude was an exercise in recycling, delayed the introduction of a 5ft 8ins mixed traffic engine, and was entirely down to the Hall’s operating success. Collett did finally introduce a 5ft 8ins mixed traffic design – the “Grange” class, from 1936, more than a decade later.

Initially, the first 14 Halls were sent out to the West Country and based at Laira and Penzance, but as more were built, they were soon spread out across the network, and by 1947; some 30 depots had an allocation of the Hall Class.  From their earliest days, workings normally associated with Halls were as varied as the names they carried, from freight, empty stock, stopping and express passenger. Only the prestigious ‘Cornish Riviera’ express was excluded from their range, but in later years, even this was overcome.

Barring engine 4941 “Bowden Hall”, which received a direct hit from a bomb in WW2, most of the class survived into BR days unscathed, and remained so until around 1961, and as dieselisation progressed rapidly on the Western Region, only 50 Hall Class engines were at work in 1965.

The Modified Halls of course suffered similar fate at the end of steam, but they had earned a reputation as speedy machines, and were well though ouf by enginemen and maintenance crews alike. The various changes to their design and construction certainly seemed to add to their value as mixed traffic designs, and coupled with their Collett progenitors, they were indeed a mixed traffic masterpiece, shared by three different CMEs of the old GWR.

After Life

Perhaps unsurprisingly, no fewer than 11 of the Hall and 6 of the Modified Hall class engines were rescued from the breakers’ torches, and now ply their trade on a number of Britain’s Heritage Railways. There are 3 Hall Class and 3 Modified Hall Class fully operational, with 4 of the Halls either being overhauled or restored, whilst 4920 is listed as stored on the South Devon Railway. Perhaps most interestingly, a Hall Class achieved superstar status thanks to Harry Potter and J.K. Rowling – 5972 “Olton Hall” is now a static exhibit at the Warner Brothers Studios.

Of the Hawksworth Modified Halls 4 are fully operational, with one being overhauled at the time of writing, and the final member 6984 “Owsden Hall” being restored at the Buckinghamshire Railway Centre.

Preserved Hall Class Engines

Preserved Halls

Preserved Modified Hall Class Engines

Preserved Modifieds

Further Reading & Links:

  • “GWR Two Cylinder 4-6-0s and 2-6-0s, Rodger Bradley,
    • Pub; David & Charles 1988; ISBN; 0715388940
  • “The GWR Mixed Traffic 4-6-0 Classes”, O.S.Nock,
    • Pub; Ian Allan 1978; ISBN; 0711007810
  • “Great Western Steam”, W.A.Tuplin,
    • Pub; George Allen & Unwin 1982; ISBN; 0043850359
  • “The Great Western at Swindon Works”, Alan S Peck;
    • Pub; Ian Allan 1998; ISBN; 9781906974039

 

Raveningham Hall video (Modified Hall Class)

Rood Ashton Hall video (Hall Class)

-oOo-

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