Class 12 (Locobase 2941)

Holland (1972, II) says these powerful engines were probably the largest non-articulated locomotives running on sub-standard gauge in the world at the time of their introduction. A photograph emphasizes the large-diameter boiler, Belpaire firebox, and cab on relatively small drivers.

Intended to haul 1,400 tons, these behemoths accomplished their task easily, which prompted several repeat orders. North British produced the first 8 (1494-1501) in 1912 and added 1502-1509 in 1913 and 1510-1519 in 1915.

Beyer, Peacock & Company supplied 20 in 1922 (1857-1878) with less superheat; see Locobase 7522

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Class 12 (Locobase 7522)

Data from 1946 Beyer, Peacock catalogue hosted on Martyn Bane's website at [] (accessed 21 May 2006).

Batch #01830 (works# 5988-5997, 6003-6012) (Production data from The Beyer, Peacock production list -- [], last accessed 29 May 2006).

These were repeats of the Class 12, but with a substantially different boiler.

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Class 12A (Locobase 2947)

Similar to the pre-war Class 12s, these engines added a combustion chamber ahead of the copper Belpaire firebox. This shortened the boiler tube length. That may have been enough to make this "a superlative locomotive," although the 30% increase in firebox heating surface didn't hurt. Holland (1972, II) says its steaming capabilities were "phenomenal." Even the 11" (279 mm) piston valves seem relatively capacious for a Cape Gauge Mountain type.

North British supplied the first batch of 20 in 1919, works numbers 21738-21754.

Later orders included:

2111-2125 from North British in 1921, works numbers 22751-22765.

1540-1545 from Henschel in 1928 (works numbers 21046-21051), followed by 1546-1550 (works 21428-21432), and 2103-2110 (works 21433-21440) in 1929; and

2126-2138 from North British (works 23891-23903), also in 1929.

Some were later reboilered, but not with the standard series. See Class 12AR.

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Class 12AR (Locobase 2965)

The already successful Class 12As were taken in hand during World War II by then Chief Mechanical Engineer Dr. MM Loubser. Although the tractive effort was unchanged, the tube & flue arrangement was considerably different. It's not clear from Holland (1972, II) how many Class 12s received the new boiler, but at 3 were so served.

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Class 12B (Locobase 2948)

Data from Holland (1972, II), p. 38-40. See also DeGolyer, Volumel 63, pp. 119; and Cdr J Plomer, "A Long Line of Mountains", The Railway and Locomotive Historical Society Bulletin, No. 122 (April 1970), pp. 7-23. Works numbers were 52476, 52558-52559, 52583-52584 in November 1919; 52649-52651, 52690-52693, 52712-52713, 52723, 52742, 52754-52767 in December 1919.

These were post-World War I repeats of the Class 12 and they too had the 11" (279 mm) piston valves and a copper Belpaire firebox. Plomer found Eddystone "went to some trouble to maintain 'South African appearance, and as the photograph shows, they did well." In particuler, the crews liked the "roomier cabs and well-laid out controls."

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Class 12R (Locobase 13109)

Data from Holland Volume II (1972), p. 82. See Locobase 13103 for a brief comment on AG Watson's drive to put standard boilers under as many classes of steam locomotives as he could.

Both the 12 and 12B class Mountains were reboilered to a common standard, in this case the Standard No 2 boiler fitted to several 4-8-2 classes. Compared to the earlier locomotives (Locobases 2941, 7522, 2948), the new boiler was substantially smaller. The grate's area shrank by a lesser amount.

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Class 14 (Locobase 2778)

Data from "The Demand for Railroad Equipment in South America and Africa," Railway and Locomotive Engineering, Volume XXXII [22], No 6 (June 1919), pp. 163. See also "Large 4-8-2 Locomotives, Natal Section, South African Railways", Locomotive Magazine, Volume XIX [19] (15 October 1913), pp. 231-233; Holland, Volume II, p. 24; and South African Railways and Harbors 8 - 1941 Locomotive Diagrams supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection..

Low-drivered Mountains designed by DA Hendrie. OS Nock (RWC IV, pl 155) described them as among the most powerful engines then running in South Africa. The first 45, bought in two batches in 1913-1915 (works numbers were 3542-3562, 3605-3614 in 1914, 3630-3644 in 1915) were the largest engines built by the Stephenson firm up to that time. Beyer, Peacock & Co delivered another 15 (works numbers were 5877-5891 in 1915.).

All of the class were delivered with Belpaire fireboxes. The 1941 diagrams show some changes including an increase in superheater area to 540 sq ft (50.17 sq m), grate area to 37 sq ft (3.44 sq m), engine weight growth to 212,352 lb (96,321 kg) and tender water capacity to 4,600 Imperial gallons (5,520 US gallons; 20,893 litres).

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Class 14A (Locobase 13092)

Data from Holland, Volume II, p. 24-25. Works numbers were 20568-20587 and 20822-20842.

Class 14 Mountains were an instant success upon their introduction, so D A Hendrie created a second class of very similar engines with smaller boilers. The weight reduction achieved, principally in axle loading, would allow them to run on the Cape Eastern main line out of East London.

They didn't prove particularly suitable for that run, Holland says, although he doesn't spell out why. So they were sent to work in the Transvaal where they "...were very popular engines, being free-steamers, low on maintenance costs and trouble-free." What more could one ask of a steam locomotive?

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Class 14C (Locobase 2949)

Data from Holland, Volume II (1972), pp. 34-36. See also Cdr J Plomer, "A Long Line of Mountains", The Railway and Locomotive Historical Society Bulletin, No. 122 (April 1970), pp. 7-25. They arrived in batches, as shown in the following (year, then works numbers): 1918 58637-58650-58656 in 1918-1919; 60265-60274, 60546-60565 in 1919; 63075-63087 in 1922.

Holland notes that DA Hendrie set out the specifications, but MLW actually designed these engines and thus followed American practice. Plomer speculated that the Canadian Alcos took the order in part because "'Empire Preferences' gave a lower rate of duty."

Their Belpaire fireboxes were relatively shallow when compared to their grate areas. Holland commented that they had "rather bad teething troubles" but gave good service once the bugs had been ironed. out. Plomer recounts just how bad the problems could be as he rode in a Durban-Johannesburg express train that moved more and more slowly as it scaled grades in an example of hot bearings. Examination determined that the class's side and connecting (North American main) rods proved too heavy for the bearings. Grease lubrication reduced the problem "considerably"

Once remedied, the 14Cs proved "excellent engines."

Later on some of these engines were modified for branch-line operation by reducing axle loads and rebalancing. They were then designated 14CB; unmodified engines were redesignated 14CM. Some CBs became CRBs with the fitting of the No 2 boiler on which the SAR standardized in the 1930s.

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Class 14R/14CRM/14CRB (Locobase 13110)

Data from Holland Volume II (1972), p. 82. See Locobase 13103 for a brief comment on AG Watson's drive to put standard boilers under as many classes of steam locomotives as he could.

The 14R fitted the Standard No 2 boiler fitted to several 4-8-2 classes to several 14 subclasses (14/14A/14C/14CB). The 14As were a bit lighter and smaller, so the new adhesion weight came 87 tons 6 cwt (195,552 lb/88,701 kg). Still lighter after reconstruction were the North American-built locomotives (Locobase 2949), which weighed in several tons lighter.

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Class 15 (Locobase 2917)

Data from Holland, Volume II (1972), pp. 26. Works numbers were 20364-20373 in 1914.

These engines preceded the more famous Class 15A (Locobase 2865) and gained fame for their unprecedented size and weight. They were, says Holland, "...the largest non-articulated locomotives in the country at that time and were the subject of much comment." The design's one signficant shortcoming was their tubes and flues were too long. The 15As, which followed quicky, differed only in reducing the tube length to 19 ft and adding a combustion chamber for better steaming.

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Class 15A (Locobase 2865)

Data from Holland, Volume II (1972), pp. 26-27.

An evolution of the narrow-gauge Mountain that South Africa saw in abundance. These Belpaire-boilered locomotives were, "despite their relatively small coupled wheels,...free- and fast-running engines" says OS Nock (RWC V, pl 51), who goes on to note that they easily hit the 55-mph limit.

DA Hendrie, who designed these and many other successful SAR engines, addressed the one weakness in the prototype 15 class engines by reducing the tube length and including a combustion chamber. The resulting locomotive is described by Holland as "one of the best class of main-line, mixed-traffice locomotives to see service in South Africa ...[they] workd in all parts of the country, were reliable, free-steaming, fran up high mileage figures between major overhauls, and can well be considered one of Hendrie's finest locomotives ...They are a real utility type and have given excellent results on both goods and passenger work."

North British built the lion's share, delivering 67 locomotive bearing the following road and works numbers:

1571-1575 20556-20560 1914

1781-1788 20843-20850 1914-1915

1789-1798 21054-21063 1915

1799-1804 21436-12441 1916

1805-1808 21502-21505 1917

1809-1828 21718-21737 1920

2080-2100 22736-22750 1921

Beyer, Peacock, & Co. delivered 30:

1839-1858 5955-5974 1920

1961-1970 5978-5987 1921

Maffei completed the class with 21:

2080-2100 5625-5645 1925

The very last Maffei was delivered with Lentz poppet valves, but soon received the standard valve gear and piston valves.

Some of the later series may have had their superheater area increased to 549 sq ft.

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Class 15AR (Locobase 13111)

Data from Holland, Volume II (1972), p 84. See Locobase 13103 for a brief comment on AG Watson's program to install standard boilers on as many classes of SAR locomotives as possible.

Built with Belpaire boilers originally, both the 15 and 15A classes (Locobases 2917 and 2865) lost that distinctive, square-shouldered look when they were fitted with the new Standard No 2A boiler. Those with a steel firebox weighed slightly less than the copper-firebox locomotives shown in the specs. Ex-15s lost some heating surface and superheater area, Ex-15As saw less dramatic drop. Weight changed little.

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Class 15B (Locobase 2950)

Data from Holland, Volume II (1972), pp. 26-27. See also "4-8-2 Type Locomotives for the South African Railways", Locomotive Magazine, Volume XXV [25], Whole no 317 (15 January 1919); and Cdr J Plomer, "A Long Line of Mountains", The Railway and Locomotive Historical Society Bulletin, No. 122 (April 1970), pp. 7-25. Works numbers were 58440-58449 in 1917 and 61424-61443 in 1922.

These were repeats of the 15As (Locobase 2865) with identical cylinder dimensions, similar Belpaire firebox and boiler, but delivered by the MLW. Like the 15A, the Belpaire fireboxes on the 15Bs encompassed an impressive amount of heating surface area to which a combustion chamber contributed. 11" (279 mm) piston valves admitted steam to the cylinders.

SAR mechanics later fitted bushings in the cylinders to reduce the diameter to 21 1/4"; steam pressure was raised to 190 psi to compensate.

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Class 15BR (Locobase 13112)

Data from Holland, Volume II (1972), p 84. See Locobase 13103 for a brief comment on AG Watson's program to install standard boilers on as many classes of SAR locomotives as possible.

Compared to the original Montreal-built 15Bs (Locobase 2950), those refitted with the Standard No 2A boiler had more heating surface area and more superheater surface. They lost some weight as well.

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Class 15CA (Locobase 2916)

Data from Holland, Volume II (1972), pp. 46. See also DeGolyer, Vol 79, pp. 522+.

When frame-cracking under the front of the firebox appeared on Baldwin's 15C, the design was slightly modified to widen the frame with a bridle casting under the firebox. (As with the 15C, the firebox heating surface included 23 sq ft/2.15 sq m of arch tubes.) This remedied the only weak spot in this design and four different builders supplied engines over the next 4 years:

2039-2059, 2072-2073 from Alco 1926 (works numbers were 66986-67008)

2074-2077 from Baldwin 1929 (works numbers were 58307-58308 in March 1925 and 58708-58717 in September.)

2801-2810 from Breda (works numbers were 2236-2245 in 1929).

2811-2839, 2840-2057 from North British (23774-23802 in 1928, 24008-24025 in 1930).

Some later had their driver diameters increased to 60" and boiler pressure to 210 psi. These good-looking engines stayed in service for decades, being, in Holland's words, "...comparatively trouble-free, good steamers and capable of handling a heavy load, exceeding that of any other locomotives so far employed on this section."

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Class 15CB (Locobase 2867)

Data from Holland, II (1972). See also DeGolyer, Volume 72, pp. 420+; and Cdr J Plomer, "A Long Line of Mountains", The Railway and Locomotive Historical Society Bulletin, No. 122 (April 1970), pp. 7-25. Works numbers were 58307-58308 in March 1925, 58708-58717 in September..

These were the first of the big-boilered Mountains on the Cape gauge, about which OS Nock (RWC V, pl 111) says the only dimension that was "sub-standard" was the rail gauge itself. Plomer called them "the biggest jump in non-articulated power since the first Hendrie Mountains. He also took the opportunity to contend that "[s]ome of the best ambassadors ever had were the foreign representatives of those two big locomotive bulders [i.e. Baldwin and Alco]."

Known as "Big Bill", this design, wrote Holland, introduced many modern features to the SAR including boiler top feeds, grease lubrication, Sellar's drifting valves, and self-cleaning smokeboxes. Firebox heating surface included 23 sq ft (2.15 sq m) of arch tubes. Specifically designed for the "long haul", the engines also had to allow them to traverse curves of 300 feet radius "with a super-elevation of 5" [127 mm] on the outer rail.")

They hauled both passenger and freight. Big Bills were known as powerful, good steamers, relatively trouble-free (except for intial frame cracking under the front of the firebox, which was repaired). Some engines were delivered with 23" (584 mm) cylinders. Some had steel fireboxes, others copper with the copper firebox examples weighing about 3,000 lb (1,359 kg) more.

The frame-cracking problem led to the 15CA, at which point the 15C was renamed the 15CB (for Baldwin) to distinguish it.

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Class 15E (Locobase 2962)

Data from Holland, Volume II (1972), p. 72-73. Stephenson works numbers were 4090-4109 in 1935 and Henschel & Sohn works numbers were 23000, 23101-23115 in 1937.

Firebox heating surface included 26 sq ft of arch tubes.

A further development of the Mountain, the 15Es had a larger boiler than the CA/CBs that with the higher drivers allowed their profitable use all over the country.

Holland notes that RC poppet valve gear shortcomings that showed when running in reverse gear were remedied by polishing and grinding the forward and reverse cam profiles (a task he had while working at the Salt River shops). About that task, he comments: "It was a toubh job as the final finish was done by hand on a polishing buff, and they had to be as smooth as glass. Not a line or scratchwas permitted on the surface, as with the expansion and contraction when in service they soon developed into cracks and the eventual breakdown of the cam."

Robert Stephenson & Company built the first 20; Henschel & Sohn delivered 16 more. Although these were fast engines, the identical 15Fs that soon followed had Walschaert's radial gear.

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Class 15F (Locobase 2868)

These follow-on orders were identical to the Class 15Es that had entered service a few years earliers, but used Walschaerts gear instead of RC poppet valve gear. Firebox heating surface included 26 sq ft of arch tubes.

Berliner Maschinenbau delivered the first 7 in 1938 and Henschel & Sohn produced 12 in the same year. North British delivered 44 in 1939. A break in deliveries caused by World War II ended in 1944 when Beyer, Peacock produced 30 and North British delivered 60. The last batch of 100 came from North British in 1948.

In 1971, all of the engines in this class remained in service.

OS Nock (RWC VI) and Holland (1972, II)

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Class 19/19B (Locobase 2954)

Data from Holland, Volume II (1972), pp.57-59. Works numbers were 9279-9282 and 9827-9840 in 1930.

Firebox heating surface included 13 sq ft of arch tubes.

These lightweight Mountains were, says Holland "...an outstanding success [which] earned a reputation for reliability, easy handling, long periods between overhaul, and economical operation." Class 19B, delivered in 1930, had a leading bogie stretched by 2 inches, which improved cylinder clearances on sharp curves.

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Class 19A (Locobase 2955)

Data from Holland, Volume II (1972), pp. 62-63.

Firebox heating surface included 15 sq ft of arch tubes.

Some SAR branch-lines had rail too light even for the Class 19s delivered in 1928 and the Swiss works supplied these to fill the deficiency. Even though they were grouped in the same general class, the SLMs had less cylinder volume, smaller boilers, and smaller drivers. "Like the 19 class," said Holland,"they are good locomotives."

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Class 19AR (Locobase 13114)

Data from Holland, Volume II (1972), pp. 87. See Locobase 13103 for a brief comment on AG Watson's program to install standard boilers on as many classes of SAR locomotives as possible.

To update the Swiss branch-line Pacifics, the SAR fitted Standard No 1A boiler. The result was more heating surface and more superheater area (an unusual outcome for the boiler upgrade program). Weight decreased slightly.

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Class 19BR (Locobase 13115)

Data from Holland, Volume II (1972), pp. 88. See Locobase 13103 for a brief comment on AG Watson's program to install standard boilers on as many classes of SAR locomotives as possible.

Class 19 and 19Bs (Locobase 2954) had the greater cylinder volume than the 19As, which was faithfully reflected in the 1930s upgrade. A Standard No 1A boiler was smaller than the original vessel as was the grate area. Weight decreased slightly as well.

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Class 19C (Locobase 2958)

Data from Data from D F Holland, Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1972), pp. 68-70.

Firebox heating surface included 16 sq ft of arch tubes. According to Holland, AG Watson found that he could have RC poppet valve gear on these engines for an additional 400 pounds in price and changed the order from 19Bs to these 19Cs. Noted that many other changes occurred as well, such as larger boiler tubes and a few more flues. Also, Holland notes, these engines introduced a force-balancing philosophy that reduced the percentage of reciprocating parts balanced from the usual 50-75% to 20%. Result: "This effected a big decrease of vertical 'hammer blow,' and at 50 mph it did not exceed 0.9 tons [2,000 lb] on any wheel."

This proved of tremendous value when procuring later locomotives for the Cape gauge, because the lower hammer blow allowed for higher axle loadings " exceeding those permitted on many other railways in the world for comparable weights of rail."

Class 19D engines followed in 1937; see Locobase 12790.

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Class 19D (Locobase 12790)

Data from D F Holland, Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1972).

See Locobase 2958 for the 19C, which introduced the RC poppet valve gear on SAR Mountains. As in the 19Cs, firebox heating surface included 16 sq ft of arch tubes. According to Holland, the tweaks included straighter steam passages and even longer lap and greater travel in the valve gear.

The Ds were known as "Dollies" and they were quite successful. Deliveries flanked the World War II years and came from three different nations' builders as follows:

Road numbers Builder Works numbers Year

2506 - 2525 Krupp 1618-1637 1937

2526 - 2545 Borsig 14643-14662 1937

2626 - 2640 Skoda 921-935 1938

2641 - 2680 Krupp 1821-1843, 1847-1863 1938-1939

2681 - 2720 Borsig 14732-14771 1938-1939

2721 - 2770 Stephenson 7191-7200, 7244-7283 1945-48

3321 - 3370 North British 26041-76090 1948

Some of the pre-war engines were delivered with prominent steam domes, others with domeless boilers. The Friends of the Rail account of their 19D comments that the reason for the domeless boiler apparently died with the designers. The North British engines had very large "torpedo" tenders that resembled US railroads' Vanderbilt tender.

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Class 23 (Locobase 2881)

Firebox heating surface included 26 sq ft of arch tubes.

The ultimate Cape gauge Mountain for the SAR, being similar to the 15Fs and also designed by WAJ Day, but with greater driver diameter and higher boiler pressure. These engines had mechanical stokers.

2552-2558,3286-3330 Berliner Maschninenbau 1938, 1939

2559-2571, 3201-3285 Henschel & Sohn 1938, 1939

As with other modern SAR power, they had the size and power of standard-gauge engines and operated well into the 1970s.

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Class 3A (Locobase 10735)

Data from "American Locomotives for Natal," The Locomotive Magazine, Volume XV [15] (15 November 1909), p. 204. See also Holland, Volume I (1972), pp. 103-105 and Cdr J Plomer, "A Long Line of Mountains", The Railway and Locomotive Historical Society Bulletin, No. 122 (April 1970), pp. 7-25. Works number was 46176 in July 1909.

This single Mountain --nicknamed "Maud Allen" likely for reasons described below-- had unusual cylinder dimensions in that they were square; that is, the bore was exactly equal to the stroke. In keeping with Hnedrie preferences, the boiler used a Belpaire firebox. Although a loner, Maud Allen established several key innovations. In addition to the superheater, she used piston valves and, of more fundamental consequence, a bar frame.

One was the of the earliest American locomotives built or exported with a superheater,

the design reflected the tendency to reduce boiler pressure when adding a superheater to the boiler. Before very long, that practice would be supplanted by a desire to get as much additional power out of the steam as possible.

The design had a Belapaire firebox and piston valves.

Compared to Hendrie's Ds, which were not superheated, Holland finds the Maud Allen to have been "...more economical in fuel and water consumption". As might be imagined from the 3.07 adhesion factor, Maud could be very slippery when starting, particularly in rain and even mist.

(Note: Maud Allen achieved some notoriety at around the time the Alco 4-8-2 arrived on the road for her performances as the Salome Dancer.. Several cities insisted on her excluding the dance from her show and Manchester banned her entire preformance.

She continued to dance into the 1930s and lived into the 1950s.

See "Maud Allen: The Salome Dancer", a 16 May 2010 entry on the Women's History Network website at at [], last accessed 1 November 2022.)

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Class 3B (Locobase 2940)

Data from Holland Volume II (1972), p. 20. Works numbers were 19597-19601 and 19688-19692.

The first DA Hendrie design to have both a superheater and piston valves. Holland adds that they used "... a new design of leading bogie with cast-steel frames and three-point suspension." They were low-drivered brutes with tall, slab-sided Belpaire fireboxes and truck wheels that were large in relation to the drivers.

See Locobase 13106 for the 3BR that resulted from placing a Standard No 2 boiler on this frame in the 1930s.

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Class 3BR (Locobase 13106)

Data from Holland Volume II (1972), p. 78. See Locobase 13103 for a brief comment on AG Watson's drive to put standard boilers under as many classes of steam locomotives as he could.

In the case of the 3Bs of 1912, the substitution of a round-topped boiler for the original Belpaire furnace was only the start. The new Standard No. 2 boiler was much smaller and somewhat longer. It held fewer tubes of greater diameter, but more superheater flues.

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Class 3R (Locobase 13103)

Data from Holland Volume II (1972), p. 77.

AG Watson's drive to put standard boilers under as many classes of steam locomotives as he could covered a wide variety of designs. All of his boilers used 2 1/2" tubes and 5 1/2" flues; the former diameter was 6.3 mm greater than the older tubes. Grate areas usually decreased as did total direct heating surface. Weight also declined, sometimes markedly.

In updating the Hendrie Ds (Class 3) -- Locobase 13102 -- the makeover wrought bigger changes than usual. Gone was the Belpaire firebox -- Watson didn't like them -- and the saturated boiler. In their place was a moderately superheated vessel of slightly higher pressure and 150 fewer small tubes. The firebox was made of copper. Weight dropped quite a bit in the conversion as well.

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Class 4 (Locobase 13086)

Data from D F Holland, Steam Locomotives of the South African Railroads, Volume 2: 1810-1955 (New York: Drake Publishers, 1972), p. 29. See also Cdr J Plomer, "A Long Line of Mountains", The Railway and Locomotive Historical Society Bulletin, No. 122 (April 1970), pp. 7-25. Works numbers were 19242-19243.

CGR had drafted plans for a large freight-hauling engine before its absorption into the SAR and this pair of Mountains was the result. Not only were they the first 4-8-2s on the SAR, but also the only ones with saturated boilers. Fitted with a combustion chamber, they were regarded, says Holland, as "excellent steamers."

Yet Plomer reported that "performance was not up to the Hendrie engines and no more were built." He also contended that the "high running boards on these engines ...always looked odd on an otherwise modern looking engine."

Throughout their careers on the Karoo between Touws River and Beaufort West, the two were never superheated.

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Class 4A (Locobase 13091)

Data from D F Holland, Steam Locomotives of the South African Railroads, Volume 2: 1910-1955 (New York: Drake Publishers, 1972), p. 23. Works numbers were 20225-20234.

As good as the first Class 4s had proven to be, H M Beatty knew they'd be even better if they were fitted with superheaters. North British supplied this decade of locomotives that also had piston valves and outside constant-lead radial valve gear. According to Holland: "Like their prototypes, they were excellent steamers and with the modifications gave a much better performance."

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Class 4AR (Locobase 4380)

Data from locomotive diagrams published on [] . See Locobase 13103 for a brief comment on AG Watson's 1930s program to place standard boilers on as many classes as possible.

Unlike some of the other updates, the use of the No 2 Standard Boiler didn't represent that big a change. The original didn't have a Belpaire boiler; neither did its update. Heating surface dropped as did superheater area, but overall the balance remained. And as with many of the others, weight dropped considerably.

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Class D/3 (Locobase 13102)

Data from South African Railways & Harbours diagrams, supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange Collection. See also Holland Volume I (1972), pp. 103-104; and Thomas Reece, "United Kingdom Locomotive Notes", Railway Master Mechanic, Volume 34, No. 9 (September 1910), p. 407; and Cdr J Plomer, "A Long Line of Mountains", The Railway and Locomotive Historical Society Bulletin, No. 122 (April 1970), pp. 7-25. Works numbers were 18829-18833 in 1909 and 19217-19241 in 1910.

Seeking an engine that would handle the growing coal traffic, DA Hendrie ordered these Mountains. The observation in Wikipedia that Hendrie took full advantage of the trailing truck is borne out by Reece's comment that the spacing between the frame rails ahead of the Belpaire firebox was 2 ' 10 3/4" (883 mm). At that point, a transverse beam reached out to hold auxiliary frames spaced 60" (1,524 mm) apart.

Among the largest saturated-boiler locomotives to work in South Africa, the class proved rugged and versatile. Success was "immediate", claimed Plomer, "as general purpose locomotives that could and did haul freight or passenger consists with equal ease." He added that even as heavy-duty switchers in later years, "not theoretically a practical design for this work ...they must have been very sure-footed, for if they gave trouble splitting switches or climbing outside rails, I never heard the train crews complain!"

(See Plomer, pp. 13-14, for an entertaining discussion of locomotive "firsts" in which he lays out the various possible claims to the title of "first 4-8-2 Mountain" to enter service.)

Locobase is not certain, but it appears the class was superheated only when given a new standard boiler in the 1930s; see Locobase 13103.

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Class Improved A (Belpaire) (Locobase 2908)

Data from Holland, Volume I (1972), pp. 91, 93; and "Class A (Belpaire)", Reference 1 in South Aftrican Railways & Harbours 8 - 1941 Locomotive Diagrams NG supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection.

Rebuilds of the Class A tanks (Locobase 2715) undertaken by D A Hendrie. Power dimensions remained the same, but Hendrie installed chief modification was the shallower Belpaire firebox with a wider grate.

In addition to the 100 converted locomotives, the shops found they had enough spares to build 2 more completed engines in 1915.

Holland reported that these were very successful.

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Class Reid Tenwheeler /H, H2 (Locobase 10325)

Data from "Class H1 & H2", Reference 1 in South Aftrican Railways & Harbours 8 - 1941 Locomotive Diagrams NG supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection.; and Holland, Volume I, pp. 94-95.

This conversion fixed the problems encountered when the long wheelbase of the Reid Tenwheelers 4-10-2Ts (Locobase 2714) traversed the lines and points of lighter-rail, sharper-curved branch and railyards. The rigid wheelbase was cut by over four feet (1.22 m).

Thus altered, the class remained in service for decades.