Great Western 4-6-0 Locomotives in Great_Britain


Class Details by Steve Llanso of Sweat House Media

Class 36 (Locobase 9670)

Data from "New Locomotives of 1897", Railway World (January 1898), pp. 12 -13.

This atypical six-coupled Great Western engine was designed to handled coal traffic from Wales to Swindon through the Severn Tunnel "...the gradients of which," the author noted, " are long and heavy." Its purpose explains the small drivers.

The boiler and firebox represented an experiment of a different sort. William Dean was introducing the wide firebox to the GWR and this was one of his first efforts. Although his layout produced a relatively sizable grate area, the author observed that its shallowness resulted in a relatively low firebox heating surface overall.

Another novelty was the use of Serve tubes, fire tubes with internal ribs that theoretically increased heating surface area. Measured on the outside, as was standard practice in Great Britain and the United States, the boiler tubes yielded 1,402.06 sq ft. (130.26 sq m) Including the internal fins raised that figure to 2,272.53 sq ft (211.12 sq m). All wheels had outside bearings and the drivers had inside bearings as well, all held in heavy plate frames. Its appearance included a horsecollar-like rib at the front of the firebox, a long boiler, and heavy double frame.

Locobase can find little mention of this locomotive in later writings about the GWR and concludes it was not deemed the prototype of the future.


Class Albion/Lady/Saint (Locobase 13312)

Data from John Daniel's superb web site [] . See also Edward Cecil Poultney, British Express Locomotive Development (London: George Allen and Unwin, 1952), p. 47 and Brian Hollingsworth, The Illustrated Encyclopedia of the World's Steam Passenger Locomotives (London: Salamander Books, 1982), pp. 68-69. See also "2999 - Lady of Legend", Didcot Railway Centre at

[], last accessed 10 December 2023.

See Locobase 2298 for the full description of Churchward's great design series. The production series shown in the present entry got its start from the second prototype - the 98 -- in March 1903. This engine was very similar to the William Dean but with key differences most notably in the valves. The relatively puny 6 1/2-inch (165-mm) piston valve diameter in the William Dean grew to a much healthier 10 inches (254 mm). As a result, valve port lengths increased to 31.5 x 1.75 inches (800 x 44 mm) for the steam (inlet) side and 31.5 x 4.5 inches (800 x 114 mm) on the exhaust side. 98 adopted the American method of casting cylinders and piston valves in a single unit with the proper half of the smokebox saddle. 98 was named Vanguard in March 1907 and renamed Ernest Cunard in December of the same year.

Churchward sought to confirm that the 4-6-0 arrangement best suited his requirements. As part of that investigation, he completed 13 of the first 20 locomotives in the class as 4-4-2s in 1905. The first two - Albion and Abbot - were converted to Ten-wheelers by 1907. The next seven entered service as 4-6-0s and the last eleven were built as Atlantics; all of the latter retained their Atlantic arrangement until 1912-1913.

The next ten rolled out in 1906 as Lady-class locomotives (2901-2910) followed by 20 Saints (2911-2930) in 1907.

Saints were delivered with the No 1 Standard full-coned boiler, which Hollingsworth describes as Churchward's "greatest triumph". One key characteristic was top-mounted clack valves fed the cold water from the tender into a series of cascading trays, which precipitated out impurities and gradually heated the supply nearly to the temperature of the water already in the boiler. This reduced the strain that cold water on hot boiler metal might otherwise have induced.

Poultney points as well to the relatively dry steam in the boiler, which resulted from using a high firebox and a tapered boiler that "...provided adequate steam space and ...a large water area and volume at that part of the boiler where there is the greatest steam generation." Steam created under such circumstances would reduce "...the violence of the ebullition and so reduce priming at high rates of evaporation." The large steam chests at the valves eliminated a chokepoint in the steam path.

Perhaps most important is another factor Hollingsworth set out: "the exceptional precision with which all these later engines were built and prepared." The set of Saints that were delivered with superheaters were named after Courts and have their own entry; see Locobase 3576.

Some of the Saints were retired in the early 1930s, but most operated into the British Railways era before being withdrawn in the late 1940s-early 1950s. None was preserved. In 1995, the Great Western Society began work on the "new" Lady of Legend (2999) that would use the frame from Hall-class locomotive (Locobase ) Maindy Hall and the Standard No. 1 boiler. As a further nod to this class's history, the engine is designed to be convertible to a 4-4-2 layout.

Beginning in the 1970s, Great Western Society (GWS) sought to add a Saint--Lady of Legend--to the 76 Saints produced in the early part of the 20th Century. Always centered on using the Hall-class locomotive Maindy Hall (4942), the prospect of converting that engine to the tall-drivered Saint seemed out of reach. But the GWS's successful restoration of the King-class King Edward II, which began in 1990 and ended with an operational engine in 2011, encouraged the GWS to restart the Saint Project in 1995. £825,000 and 24 years later, the Lady of Legend appeared under steam in 2019.


Class Castle/40xx (Locobase 306)

Reder (1974), Hamilton Ellis in Ransome-Wallis (1959), and "Four-Cylinder Express Locomotive 'Caerphilly Castle', Great Western Railway, Locomotive Magazine, Volume XXIX [29], No 373 (15 September 1923), pp. 254-255; and "Four-Cylinder 4-6-0 Type Express Locomotives, Great Western Railway", Railway Engineer, Volume 44, No 10 (October 1923), pp. 394-396. See [] (Information by John Daniel, 2000) for details on this class, including all names; and Edward Cecil Poultney, British Express Locomotive Development (London: George Allen and Unwin, 1952), p. 139. (Thanks to Alexander Blessing for his 4 March 2022 email noting differences in tender weight and coal capacity, total wheelbase, power system weight, and road number range.)

Basically enlarged "Stars", which CB Collett introduced in the mid-1920s. Note the high boiler and grate demand factors, the small superheater, and the generally small proportions.

Indeed, a dissenting opinion from the generally high level of praise can be found in Railway Journal in October 1923. Leaving aside the high tractive effort, wrote the author, "the Great Western engine, admirable as it is in all respects, does not rank above the others in point of capacity for effective work in starting and hauling heavy trains." Comparing the factor of adhesion to those of the LNER's Pacifics,many will find it difficult to agree with the claim advanced in favour of the Caerphilly Castle as the most powerful engine in Great Britain."

Locobase notes that the FofA stood at 4.2, which is in range with most express engines. And evidence kept accumulating that showed these were indeed locomotives to envy. For one thing, they had suprisingly low coal consumption, which is attributed to careful valve design, early cut-offs, and high-calorie coal. Like most GWR engines, these had Belpaire fireboxes. (Piston valves retained the 8"/203 mm diameter of the Star valves.)They were among the most powerful express locomotives in British service in the 1920s and 1930s.

According to the website of the preserved Pendennis Castle -- [], accessed 21 June 2006 -- "Pendennis Castle's claim to fame [and consequently that of the entire class] was staked firmly in 1925 when the GWR lent the locomotive to the London & North Eastern Railway for trials against Sir Nigel Gresley's mighty new 'Pacifics' exemplified by No.4472 'Flying Scotsman'. Working 16-coach trains on the East Coast main line from Kings Cross, the stalwart 'Castle' covered itself in soot and glory, thoroughly out-performing its larger competitors. Its exploits were the talk of every schoolboy in Britain and the GWR rather cheekily sent 'Pendennis Castle' to stand alongside 'Flying Scotsman' at the 1925 British Empire Exhibition at Wembley with a notice proclaiming it to be the most powerful passenger express locomotive in Britain."

Poultney notes that the Castle Ten-wheeler handled the GNR's traffic with aplomb, a result attributable to a combination of "...better evaporation in relation to the coal fired [and] to a much more efficient use of steam in the cylinders." He cited the high gas area through the tubes (most of which were unecumbered by superheater flues) and an efficient length-to-tube-diameter ratio. The high evaporation rate coupled with the high mean effective pressure allowed "...the use of short running cutoffs resulting in good cylinder efficiencies which, with a plentiful steam supply ..." made it the equal of the larger Pacific.

Certainly Nigel Gresley was impressed and humbled enough to immediately take his Pacifics in hand for an upgrade; see Locobase 1065.

Swindon continued building new examples as late as 1950 and they continued giving good service until their retirement in the 1960s.


Class County/61xx (Locobase 3108)

See [] (Information by John Daniel, 2000) for details on this class, including all names.See also

In some respects a continuation of 4-6-0 practice that began with the "Courts", these engines, designed by FW Hawksworth, were the last in the line. Unlike other Great Western engines, however, Counties had their cylinders bolted to a main frame that ran clear forward to the buffer beam. For some reason, drivers preferred the earlier Collett-designed Ten-Wheelers and only 30 of these were built. One reason could have been the high "hammer blow" felt by the crews.

The first was delivered with a double-chimney (stack), the rest were fitted with a single chimney. In 1956, BR reduced boiler pressure to 250 psi. All of these were retrofitted with single chimneys in 1957-1958.

See a full description of a plan to resurrect 1014 County Glamorgan using a 2-8-0 8F frame at [], last accessed 28 October 2011, later succeeded by the "1014 GWR County Project - completing the set" at [], last accessed 13 May 2019.


Class Court/29xx (Locobase 3576)

Data from "The 'Court' 4-6-0 Class Express Engines, Great Western Railway", Railway Engineer, Volume 33, No 7 (July 1912), pp. 221-225. See [] (Information by John Daniel, 2000) for details on this class, including all names. Daniel does not distinguish between the two sub-classes. See also Edward Cecil Poultney, British Express Locomotive Development (London: George Allen and Unwin, 1952), p. 66 and Brian Hollingsworth, The Illustrated Encyclopedia of the World's Steam Passenger Locomotives (London: Salamander Books, 1982), pp. 68-69.

These engines were Saints (Locobase 13312) delivered with a revised full-cone boiler layout that included superheaters as well as cylinders 1/2" larger. The boiler featured Churchward's top-feed system described in the Saints entry. An unusual choice was the continued use of inside Stephenson (Williams-Howe) link motion working the valves through rocker arms.

Delivered with the inside steam pipe characteristic of the Saint class, the class later received outside steam pipes which provided a straighter steam path to the valves.

All of the Courts remained in service until the late 1940s and early 1950s.


Class Dean (Locobase 2298)

Data from John Daniel's superb web site [] . See also Edward Cecil Poultney, British Express Locomotive Development (London: George Allen and Unwin, 1952), p. 47; and George Montagu, MP, "Typical Expresses No V: The Great Western", Car: A Journal of Travel by Land, Sea and Air, Volume 1, No 12 (13 August 1902), p. 419

Prototype of the 4-6-0s that would come to dominate passenger traffic on the Great Western. Poultney points out the several features in the design that derived from Locomotive Superintendent George J Churchward's familiarity with American practice. Each cylinder was cast with a half saddle for the boiler and bolted on the centerline, an assembly that "...allows of the provision of easily arranged exhaust passages which are, at the same time, greatly simplified by the suppression of separate exhaust piping with numerous joints." The railway-wide adoption of Belpaire fireboxes, such as were found in this class, may have also been due to his experience with the Pennsylvania Railroad.

Resorting to small-diameter pistons with long strokes allowed for smaller piston valves (6 1/2"/165 mm diameter) and generous port openings in relation to the swept cylinder volume. Most of the class were delivered with "half-cone" boilers. Many then received full-cone boilers, then half-cone with superheaters, then full-cones with superheaters -- there are many variations to this.

In any event, Hollingsworth (1986) notes that the coned boilers -- Churchward's "greatest triumph" and tried in William Dean in 1900 -- fed the cold water from the tender from the top into a series of cascading trays, which precipitated out impurities and gradually heated the supply nearly to the temperature of the water already in the boiler. This reduced the strain that cold water on hot boiler metal might otherwise have induced.

The 6024 history settles a question that many might have had about the Great Western's avoidance of Pacific (4-6-2) express locomotives: "Churchward's preference for locomotive's without trailing wheels was a direct response to the need to maximise adhesion on the South Devon banks of Dainton, Rattery and Hemerdon on the West of England mainline to Plymouth, then the Great Western's most important route." In a way, the South Devon banks were "ruling grades" in more than one sense.

Perhaps most important is another factor Hollingsworth set out: "the exceptional precision with which all these later engines were built and prepared."


Class Grange/68xx (Locobase 3109)

See [] (Information by John Daniel, 2000) for details on this class, including all names.

Churchward had wanted to apply the Standard No 1 boiler and Belpaire firebox of the 20th-Century 4-6-0 series that began with the Saints (Locobase 13312) to a frame with 68" drivers. He wanted the larger engine to replace the large class of 2-6-0s that had been built from 1911-1932 (Locobase 2743). In the event, it was C B Collett who would update the Star-Court design with a new cab and the smaller drivers. The wheels, valve gear, and tenders came from 4300-class Moguls that had been retired. Cost per recycled locomotive:5,000 pounds BPS.

The plan had been to replace all 342 2-6-0s, but World War II curtailed the program after 80 had been built. According to the Betton Grange 6880 website, the reasons for the locomotive's popularity were pretty simple: "The `Granges' became noted for the readiness with which their boilers raised steam; superbly free running and impressive delivery of power when attacking steep, adverse gradients with heavy loads. It was precisely because of these properties that the Great Western allocated so many of them to the arduous duty of piloting heavy passenger and freight trains over the notoriously steep and twisting South Devon banks."

Observing that the great success could "only partly be explained in rational engineering terms", [] notes that the boilers were identical to the point of being interchangeable with those of the Halls as was smokebox draughting, "critical to a locomotive's steaming characteristics."But Betton Grange 6800 notes that both the steam chests and steam ports were larger in the Granges than in the earlier Halls and the steam ports may have helped cushion the pistons at the end of their strokes.

Very satisfactory engines, the entire class entered the British Railway era and all served until the last days of mainline steam in Britain in the mid-1960s.

As none of the Grange class was preserved, Hall-class 7927's No 1 Standard boiler is the centerpiece of an attempt to recreate the Grange style in Bretton Grange, No 6880. See [], last accessed 13 May 2019 for notes on progress oin the project.


Class Hall/49xx (Locobase 3110)

Data from [] (Information by John Daniel, 2000) for details on this class, including all names. See also the Great Western Project's summary at [], last accessed 28 October 2011.

Carrying on Churchward's No 1 Standard boiler, the Halls were identical to the Star-Court-Grange designs (Locobase 1497 & 2308, 3576, 3109, respectively) except for their 72" drivers and a slight reallocation of heating surface in favor a larger superheater. Also the steam pipes leading to the cylinders now appeared outside of the lagging and the boiler was pitched a few inches higher. 4900 was the made-over 2900-class Saint Martin which came from Swindon in 1924.

The soundness of the design, which in fact was little different from the earlier GWR 4-6-0s, was borne out by the production record. Halls were produced in 1928-1931, 1933, and 1935-1943.

Locobase 2368 describes the modified Hall design put into service after World War II.

Beginning in 1995, the Great Western Society began adapting the Maindy Hall's (4942) frame and a No 1 Standard Boiler to create a "new" Saint-class (Locobase 13312) locomotive.

A locomotive named "Hogwarts Castle", which appeared in most of the Harry Potter moviers, was portrayed by 5972 Olton Hall.


Class King/60xx (Locobase 2508)

Data from [] (Information by John Daniel, viewed 1 Oct 2004) for details on this class, including all names. It's a treat to read Daniel's opening paragraph on the Kings: See also "GWR King class 4-cylinder 4-6-0 No. 6024 King Edward I -- A Brief History", 6024 Preservation Society web page, archived at [], last accessed 29 July 2018.

In response to ever-increasing demands, CB Collett extended the Castle class (themselves enlarged Star class - see Locobases 306, 1497, & 2308, respectively), the fouer-cylinder simple layout, and the 4-6-0 express wheel arrangement to even greater dimensions. In keeping with British practice, these engines had relatively small, tapered domeless boilers using a small degree of superheat and a Belpaire firebox with a relatively small grate. Such was the confinement of the compact loading gauge that the leading truck had to be designed with outside bearings on the front axle, inside bearings on the rear one.

Like the Castles, the Kings achieved their suprisingly low coal consumption with careful valve design, early cut-offs, and high-calorie coal. Performance included owning a tonnage rating of 360 tons up the 2.4% Hemerdon grade east of Plymouth.

Hollingsworth (1982) argues that one area in which the design was unbalanced was the lack of a mechanical stoker as the boiler could generate 30% more steam than a fireman could shovel coal into the fire. The imbalance worsened, one might argue, when the class was rebuilt in the 1950s; see Locobase 4806.

"The English may have had a King Edgar, but regrettably they never had a King Elgar, which was pity as it would have been fitting name for one of the ultimate Great Western express engines. The bark of a 'King' on Hemerdon Bank had more than a whiff of 'Land of Hope and Glory' about it; this was apt for South Devon was, and still is, a land of glory and any train tackling the 1 in 40 from Plympton to Hemerdon had to have a fair degree of hope as well."

See also

[] for full data and details on the 1949 Interchange trials.


Class Manor/78xx (Locobase 3111)

Data from See [] (Information by John Daniel, 2000) for details on this class, including all names.

Glover (1967) notes that these engines had a relatively small grate area for the firebox length and points out the invisible reason for this: " the throat plate was given a forward slope between the foundation ring and the point where it met the barrel. This feature ...improves the longitudinal proportions between barrel and firebox, without bringing the front of the grate over the middle coupled axle, a course which necessitates the employment of an unduly shallow firebox."

CB Collett designed these engines as well as the Castles and Kings, but these were smaller and designed for more prosaic unnamed passenger service on lighter rail, especially in central Wales. Their Belpaire boilers measured a maximum of 63" in diameter. Like the earlier Hall class, the Manors took their wheels, valve gear, and tenders from 4300-class Moguls that were being withdrawn.


Class Modified Hall (Locobase 2368)

Data from [] (Information by John Daniel, 2000) for details on this class, including all names.

FW Hawksworth update of the Hall class (Locobase 3110), which itself was a 1925 update of the Saint class of 4-6-0 (Locobase 2298) . The most significant changes were the adoption of a one-piece frame, separately cast cylinders, use of a plate frame (as opposed to a bar frame) in the leading bogie, larger superheater (relatively speaking -- for 1944, 14.5% was miserly), better lubrication system, and modified regulator (throttle) header.

The reworking was an immediate and lasting success. Tim Overton's web site notes that these were considered good runners, in part because they could burn the poor-quality coal that became familiar to British railroaders after World War II. Richard Drew ([]) reports that these engines regularly put up excellent performances. For example, one of the class usually completed the Oxford-Paddington leg (63.5 miles) in under 56 minutes (68+ mph). A 1958 run from Reading to Taunton (106.9 miles) with 490 tons averaged 55.9 mph.


Class Modified King/60xx (Locobase 4806)

Data from [] (Information by John Daniel, 2000) for details on this class, including all names. See also "GWR King class 4-cylinder 4-6-0 No. 6024 King Edward I -- A Brief History", 6024 Preservation Society web page, archived at [], last accessed 29 July 2018.

This rebuild installed a four-row superheater that increased the superheat area by 56% and installed a double-blast pipe stack (in 1955); to make room in the constricted boiler, 16 added flues replaced 56 small tubes. Already demanding a steady supply of coal on a relatively large grate, the upgraded engine was certainly more efficient but no less hungry for fuel. Perhaps surprisingly, the engines still were hand-bombed.

Nevertheless, this class certainly succeeded in its design goals. The 6024 preservation history emphatically states that the class's longevity was "legendary". The update and tweaks meant "not only were they able to live up to their long-held reputation as load-pullers, but compared with the original locomotives, they gained greater freedom from mechanical resistance which promoted regular high-speed running, with speeds in the nineties, and on occasions, in excess of 100 mph. "

They were retired in 1962-1963. Only three were preserved--class leader King George V (6000), King Edward I (6023) and King Edward II (6024).

(NB: A court case involving an internal dispute within 6024 Preservation Trust resulted in a 2010 decision that required a 500,000 GBP payment. Such a sum could only be raised by selling the locomotive to the Royal Scot and General Trust. The GSGT's ten-year overhaul was expected to complete in 2019.)


Class Star - 4030 (Locobase 2308)

See Ahrons (1927) and "Great Western Ry Express Engines, 'Princess' Class'", Locomotive Magazine, Volume XX [20] (15 October 1914), p. 260. Later information from John Daniel's Great Western website [] (accessed February 2002) confirms that these were superheated Stars, which had been introduced in 1907 (Locobase 1479).

Like the two-cylinder engines, these had a Belpaire firebox and coned boiler. They used 8" (203 mm) piston valves to admit steam to the cylinders.

4010 arrived with a Swindon #1 superheater. John Daniel (of the excellent [] website) noted the first Star to be fitted with the Swindon #3 superheater was 4012 King Edward while it was standardized for the class with 4031 Queen Mary. Earlier engines were retrofitted beginning in 1913. The cylinders, which originally had a diameter of 14 1/4" were soon enlarged to 15" as shown in the specifications.

Ten 1908 engines-4011-4020--bore the names of Knights. Ten 1909 "Kings" (4021-4030) became "Monarchs" in 1927 to make way for the later King class 4-6-0s. 1910 saw ten " Queens", while 1913 "Prince" locomotives were the first to be delivered with the #3 superheater

Locomotives 4046-4060 were described in the LM as the Princess class, as all of the engines were named Princess nnnn or Mary, Louise, Victoria, Maud, Alice, Helena, Beatrice, Alexandra, Charlotte, Sophia, Margaret, Elizabeth, August, Patricia, and Eugeniie.

Gustav Reder wrote that when superheated, the class showed a 12% reduction in coal consumption and used 20% less water. They ran at 70 mph (113 kph) on the level and pulled 480 tons up a slight gradient.

The last ten --1922 engines 4063-4072, known as the Abbey class -- were modified in 1937-1940 and were grouped with the Castle class.


Class Star/40xx (Locobase 1497)

Data from Charles Rous-Marten, "New Type of Great Western Express Engine: An Evolution", Engineer, Volume 103 (29 March 1907), pp. 306-307. Gustav Reder, The World of Steam Locomotives ( , 1974). See also "Four Cylinder Simple Engine, Walschaerts [sic] Gear, One Eccentric Drives Two Valves", Railway and Locomotive Engineering, Volume 21, No 8 (August 1908), pp. 343-344; and "Locomotive Details--The Deeley Valve Gear", Model Engineer and Amateur Electrician, Volume 22 (10 June 1910), pp.562-563. (Thanks to Alexander Blessing for his 11 July 2023 email adding the coal capacity and correcting the adhesion and engine weights and the tender's water capacity.)

Four-cylinder Churchward design derived from the smooth-running De Glehn Compound Atlantics President and Alliance that he'd purchased for comparison a few years earlier. (Locobase 1496) The engines were simpler in layout, having four simple cylinders and one set of valve gear for each pair of cylinders (the outer set on each driven by rocking levers from the inner valve). Inside cylinders drove the leading coupled axle's crank axle and were set 180 deg apart while the commensurate cranks on each side were set 90 degrees apart. The arrangement meant there was a crank on each quarter.

Like all GWR Ten-wheelers, this class had a Belpaire firebox. The coned boiler represented a GWR hallmark and Churchward adopted an extended smokebox.

The first nine were delivered with saturated boilers holding 250 2" (50.8 mm) tubes that yielded 1,988.65 sq ft (184.75 sq m), the tenth being fitted with a Swindon No 1 superheater before it entered service.

Principal Dimensions by Steve Llanso of Middle Run Media

Class36Albion/Lady/SaintCastle/40xxCounty/61xxCourt/29xx
Locobase ID9670 13312 306 3108 3576
RailroadGreat WesternGreat WesternGreat WesternGreat WesternGreat Western
CountryGreat BritainGreat BritainGreat BritainGreat BritainGreat Britain
Whyte4-6-04-6-04-6-04-6-04-6-0
Number in Class1501713025
Road Numbers362901-2930, 2971-29904073-4099, 5000-5099, 7000-70371000-1029, 6100-61292931-2955
GaugeStdStdStdStdStd
Number Built1501713025
BuilderGWR - SwindonGWR - SwindonGWRGWR - SwindonGWR - Swindon
Year18961905192319451911
Valve GearStephensonStephensonWalschaertWalschaertStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)14.67 / 4.4714.75 / 4.5014.75 / 4.5014.75 / 4.5014.75 / 4.50
Engine Wheelbase (ft / m)27.25 / 8.3127.25 / 8.3127.25 / 8.3127.25 / 8.31
Ratio of driving wheelbase to overall engine wheelbase 0.54 0.54 0.54 0.54
Overall Wheelbase (engine & tender) (ft / m)54.52 / 16.67
Axle Loading (Maximum Weight per Axle) (lbs / kg)37,072 / 16,81640,320 / 18,28944,128 / 20,016
Weight on Drivers (lbs / kg)106,176 / 48,161121,408 / 55,070133,500 / 60,555132,384 / 60,048122,752 / 55,679
Engine Weight (lbs / kg)133,280 / 60,455157,248 / 71,327178,892 / 81,144171,696 / 77,880161,280 / 73,155
Tender Loaded Weight (lbs / kg)75,040 / 34,03896,656 / 43,842104,608 / 40,947109,760 / 49,78689,600 / 40,642
Total Engine and Tender Weight (lbs / kg)208,320 / 94,493253,904 / 115,169283,500 / 122,091281,456 / 127,666250,880 / 113,797
Tender Water Capacity (gals / ML)3120 / 11.824800 / 18.184800 / 18.184000 / 15.154200 / 15.91
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 5.50 / 5 6.70 / 67 / 6
Minimum weight of rail (calculated) (lb/yd / kg/m)59 / 29.5067 / 33.5074 / 3774 / 3768 / 34
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)54 / 137280.50 / 204580.50 / 204575 / 190580.50 / 2045
Boiler Pressure (psi / kPa)165 / 11.40225 / 15.50225 / 15.50280 / 19.30225 / 15.50
High Pressure Cylinders (dia x stroke) (in / mm)20" x 24" / 508x61018" x 30" / 457x76216" x 26" / 406x660 (4)18.5" x 30" / 470x76218.5" x 30" / 470x762
Tractive Effort (lbs / kg)24,933 / 11309.4323,093 / 10474.8231,626 / 14345.3332,582 / 14778.9624,393 / 11064.49
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.26 5.26 4.22 4.06 5.03
Heating Ability
Tubes (number - dia) (in / mm)150 - 2.5" / 64260 - 2" / 51201 - 2" / 51198 - 1.75" / 44176 - 2" / 51
Flues (number - dia) (in / mm)14 - 5.125" / 13021 - 5.125" / 13014 - 5.125" / 130
Flue/Tube length (ft / m)14.29 / 4.3614.66 / 4.4714.83 / 4.5213 / 3.9615.20 / 4.63
Firebox Area (sq ft / m2)115.83 / 10.76154.26 / 14.33163.70 / 15.21169 / 15.71154.78 / 14.38
Grate Area (sq ft / m2)35 / 3.2527.07 / 2.5129.36 / 2.7328.84 / 2.6827.07 / 2.51
Evaporative Heating Surface (sq ft / m2)2388 / 221.852143 / 199.092049 / 190.361714 / 159.291841 / 171.03
Superheating Surface (sq ft / m2)263 / 24.43265 / 24.63263 / 24.43
Combined Heating Surface (sq ft / m2)2388 / 221.852143 / 199.092312 / 214.791979 / 183.922104 / 195.46
Evaporative Heating Surface/Cylinder Volume273.64242.54169.33183.64197.25
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation57756091660680756091
Same as above plus superheater percentage57756091733391256883
Same as above but substitute firebox area for grate area19,11234,70940,88453,47239,353
Power L15049995713,05818,54016,113
Power MT314.51542.42646.92926.25868.17

Principal Dimensions by Steve Llanso of Middle Run Media

ClassDeanGrange/68xxHall/49xxKing/60xxManor/78xx
Locobase ID2298 3109 3110 2508 3111
RailroadGreat WesternGreat WesternGreat WesternGreat WesternGreat Western
CountryGreat BritainGreat BritainGreat BritainGreat BritainGreat Britain
Whyte4-6-04-6-04-6-04-6-04-6-0
Number in Class1802593030
Road Numbers1006800-68794901-4999, 5900-5099, 6900-69586000-60297800-7829
GaugeStdStdStdStdStd
Number Built1802593030
BuilderGWR - SwindonGWR - SwindonGWR - SwindonGWR - SwindonGWR - Swindon
Year19021936192819271938
Valve GearWalschaertWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)14.75 / 4.5014.7514.75 / 4.5016.25 / 4.9514.75
Engine Wheelbase (ft / m)27.25 / 8.3127.0827.09 / 8.2629.42 / 8.9727.08
Ratio of driving wheelbase to overall engine wheelbase 0.54 0.54 0.54 0.55 0.54
Overall Wheelbase (engine & tender) (ft / m)43.4053.37 / 16.2757.4652.15
Axle Loading (Maximum Weight per Axle) (lbs / kg)40,32038,19242,448 / 19,25450,400 / 22,86138,640
Weight on Drivers (lbs / kg)125,888 / 57,102123,424 / 55,984126,560 / 57,407151,200 / 68,583112,896 / 51,209
Engine Weight (lbs / kg)157,248 / 71,327165,760 / 75,188168,000 / 76,204199,360 / 90,428154,336 / 70,006
Tender Loaded Weight (lbs / kg)96,65689,600101,136 / 45,875104,608 / 47,44989,600
Total Engine and Tender Weight (lbs / kg)253,904 / 71,327255,360 / 75,188269,136 / 122,079303,968 / 137,877243,936 / 70,006
Tender Water Capacity (gals / ML)48004200 / 13.264200 / 15.914800 / 16.674200 / 13.26
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 5.506 / 6 6.60 / 6 7.20 / 7 7.70 / 6
Minimum weight of rail (calculated) (lb/yd / kg/m)70 / 3569 / 34.5070 / 3584 / 4263 / 31.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)80.50 / 204568 / 172772 / 182978 / 198168 / 1727
Boiler Pressure (psi / kPa)225 / 13.80225 / 15.50225 / 15.50260 / 17.90225 / 15.50
High Pressure Cylinders (dia x stroke) (in / mm)18" x 30" / 457x76218.5" x 30" / 470x76218.5" x 30" / 470x76216.25" x 28" / 413x711 (4)18" x 30" / 457x762
Tractive Effort (lbs / kg)23,093 / 10474.8228,877 / 13098.4027,273 / 12370.8441,898 / 19004.6427,338 / 12400.32
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.45 4.27 4.64 3.61 4.13
Heating Ability
Tubes (number - dia) (in / mm)287 - 2" / 51176 - 2" / 51176 - 2" / 51171 - 2.25" / 57158 - 2" / 51
Flues (number - dia) (in / mm)14 - 5.125" / 13014 - 5.125" / 13016 - 5.125" / 13012 - 5.125" / 130
Flue/Tube length (ft / m)14.66 / 4.4715.20 / 4.6314.83 / 4.5216.45 / 5.0113.04 / 3.97
Firebox Area (sq ft / m2)157.94 / 14.68154.78 / 14.38154.78 / 14.38193.50 / 17.98140 / 13.01
Grate Area (sq ft / m2)27.62 / 2.5727.07 / 2.5227.07 / 2.5234.30 / 3.1922.10 / 2.05
Evaporative Heating Surface (sq ft / m2)2411 / 224.071687 / 156.781841 / 171.102202 / 204.651426 / 132.53
Superheating Surface (sq ft / m2)253 / 23.51263 / 24.44313 / 29.09160 / 14.87
Combined Heating Surface (sq ft / m2)2411 / 224.071940 / 180.292104 / 195.542515 / 233.741586 / 147.40
Evaporative Heating Surface/Cylinder Volume272.87180.75197.25163.81161.39
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation62156091609189184973
Same as above plus superheater percentage62156883688399885470
Same as above but substitute firebox area for grate area35,53739,35339,35356,34734,650
Power L110,93512,94414,41215,05310,292
Power MT574.50693.62753.15658.46602.94

Principal Dimensions by Steve Llanso of Middle Run Media

ClassModified HallModified King/60xxStar - 4030Star/40xx
Locobase ID2368 4806 2308 1497
RailroadGreat WesternGreat WesternGreat WesternGreat Western
CountryGreat BritainGreat BritainGreat BritainGreat Britain
Whyte4-6-04-6-04-6-04-6-0
Number in Class7130739
Road Numbers6959-6999, 7900-79296000-60294030-40724000-4029
GaugeStdStdStdStd
Number Built71639
BuilderGWR - SwindonGWRGWR - SwindonGWR - Swindon
Year1948195519131907
Valve GearWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)14.75 / 4.5016.25 / 4.9514.75 / 4.5014.75 / 4.50
Engine Wheelbase (ft / m)27.25 / 8.3129.42 / 8.9727.25 / 8.3127.25 / 8.31
Ratio of driving wheelbase to overall engine wheelbase 0.54 0.55 0.54 0.54
Overall Wheelbase (engine & tender) (ft / m)53.54 / 16.32
Axle Loading (Maximum Weight per Axle) (lbs / kg)43,120 / 19,55950,400 / 22,861
Weight on Drivers (lbs / kg)128,800 / 58,423151,200 / 68,583124,096 / 56,289124,119 / 56,299
Engine Weight (lbs / kg)169,792 / 77,016199,376 / 90,436169,344 / 76,813169,366 / 76,823
Tender Loaded Weight (lbs / kg)105,592 / 47,896104,608 / 47,44989,600 / 40,64289,600 / 40,642
Total Engine and Tender Weight (lbs / kg)275,384 / 124,912303,984 / 137,885258,944 / 117,455258,966 / 117,465
Tender Water Capacity (gals / ML)4800 / 18.184400 / 16.674200 / 15.91
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 6.60 / 6 7.20 / 7 6.70 / 6.10
Minimum weight of rail (calculated) (lb/yd / kg/m)72 / 3684 / 4269 / 34.5069 / 34.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)74 / 188078 / 198180.50 / 204580.50 / 2045
Boiler Pressure (psi / kPa)225 / 15.50250 / 17.20225 / 15.50225 / 15.50
High Pressure Cylinders (dia x stroke) (in / mm)18.5" x 30" / 470x76216.25" x 28" / 413x711 (4)15" x 26" / 381x660 (4)14.25" x 26" / 362x660 (4)
Tractive Effort (lbs / kg)26,536 / 12036.5440,286 / 18273.4427,797 / 12608.5225,086 / 11378.83
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.85 3.75 4.46 4.95
Heating Ability
Tubes (number - dia) (in / mm)145 - 2" / 51115 - 2.25" / 57176 - 2" / 51250 - 2" / 51
Flues (number - dia) (in / mm)21 - 5.125" / 13032 - 5.125" / 13014 - 5.125" / 130
Flue/Tube length (ft / m)15.20 / 4.6316.45 / 5.0114.83 / 4.5215.20 / 4.63
Firebox Area (sq ft / m2)154.90 / 14.40195 / 18.12154.70 / 14.37154.78 / 14.38
Grate Area (sq ft / m2)27.07 / 2.5234.30 / 3.1927 / 2.5127.07 / 2.51
Evaporative Heating Surface (sq ft / m2)1736 / 161.342013 / 187.081841 / 171.032143 / 199.09
Superheating Surface (sq ft / m2)295 / 27.42489 / 45.45263 / 24.43
Combined Heating Surface (sq ft / m2)2031 / 188.762502 / 232.532104 / 195.462143 / 199.09
Evaporative Heating Surface/Cylinder Volume186.00149.75173.10223.26
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation6091857560756091
Same as above plus superheater percentage700410,29068656091
Same as above but substitute firebox area for grate area40,08058,50039,33234,826
Power L115,35817,86514,1399174
Power MT788.63781.46753.56488.85

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