Cape Government / Cape Government Railways / South African Railways 4-6-0 Locomotives in South_Africa


Class Details by Steve Llanso of Sweat House Media

Class 6B/6C (Locobase 16122)

Data from South African Railways & Harbours 9 -1941 Locomotive Diagrams supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange. See also A E Durrant, The Smoke that Thunders (Harare, Zimbabwe: African Publishing Group, 1997), p. 9. Most were produced by Neilson & Company with the last 21 coming from Sharp, Stewart

The above-mentioned diagram book shows several versions of the Class 6 Ten-wheeler. This was one of the more common. 6Bs came from the Cape Government Railways, 6Cs from the Oranje-Vrijstaat Gouwerment-Spoorwegen (OVGS) (later Central South African) and weighed about 1,000 lb more. Several received Belpaire boilers that increased total evaporative heating surface area; see Locobase 16124.

Durrant reports that B Class 525-527 were to have gone to the Bechuanaland Railway in what became Rhodesia and were in fact delivered to that line as their 1-3. But they were immediately sold ("presumably due to cash flow problems") to the CGR. The CGR apparently leased them back to the railway to support a service to Bulawayo, although Durrant notes that this couldn't be confirmed.

The CGR absorbed them into its own set of Class 6 locomotives (see Locobase 10153) and fitted two of the class with Belpaire boilers. Like most CGR/SAR locomotives, these operated for decades. 527 was withdrawn in January 1951, 525 in 1956, and 526 in September 1957.


Class 6C - Belpaire (Locobase 16124)

Data from South African Railways & Harbours 9 -1941 Locomotive Diagrams supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange.

P A Hyde, Chief Locomotive Superintendent of the Central South African Railways, thought Belpaire boilers improved a locomotive's steaming qualities and, beginning in 1904, replaced several of the round-top boilers in the Class 6 Ten-wheelers with the square-shouldered variant. Not only was the boiler simply bigger, but it was pressed to a higher degree, which yielded more starting tractive effort. The cost was greater weight. Wikipedia reports that coal consumption dropped by 5% despite the heat system's greater size while typical trailing loads rose by 12%.

At least of these was later superheated; see Locobase 16125.

In the 1930s, the SAR's Chief Mechanical Engineer A G Watson was faced with a variety of boilers installed in many of his railway's classes. Many of them combined the Belpaire firebox with a combustion chamber, features that Watson disliked because of their higher maintance cost.


Class 6C - Belpaire-superheated (Locobase 16125)

Data from South African Railways & Harbours 9 -1941 Locomotive Diagrams supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 16124 describes the Belpaire boiler upgrade to many of the 6Cs in CSAR service. At some point, at least boiler number 7215 went through a simple conversion to install an 18-unit superheater in place of 111 small tubes.


Class 6D/6H (Locobase 10153)

Data from "Cape Government Railways," The Locomotive Magazine, Vol V (July 1900), p. 105. Additional information from the South African Railways historical website [], last accessed 15 April 2009.

According to the Old Steam Locomotives in South African blog, authored by Leith Paxton and David Bourne ([], last accessed 3 April 2010): "All the engines of the 6th class were regarded as having a splendid record of reliability, and low cost of repairs. In 1894 the General Manager, Mr. Elliot reported: 'These engines will render practicable an increase in speed that will admit of a train being run from Cape Town to Johannesburg in 48 hours.'"

The locomotive whose dimensions are showcased in LM article is described as typical of the 6th class Ten-wheelers that had entered CGR service over the previous five years. They were supplied by Dubs, Sharp, Stewart, and Neilson, Reid, all of Glasgow (and soon to be united as North British Locomotive Company).

"These engines are the standard type, " the author stated, " used for working the passenger and goods traffic over the Western system, including the Rhodesia Railways to Buluwayo, over the northern portions of the Midland and Eastern systems." Reflecting the Boer War that seemed about to end, but which had more than a year to run, the author added, "[A]nd they have worked the bulk of the military traffic up to the present."

Of the first 196 engines, however, only the 32 6Ds had the 18-sq ft grate; all of the others had 16.6-sq ft grates and there were a lot of them - 170 in all with the 16.6 sq ft grate:

Class Builder Year Road numbers

6 Dubs 1893 139-160, 353-370 401-440

6A Dubs & SS 1895 161-201, 371-374, 575-576, 660-662

441-489

6B NR 1897 202-235, 577-584, 587-593, 490-540

595-600, 663-664

6C all three 1896 346-364, 366-369 541-564

6D (18 sf) NR 1898 234-269, 585-586, 594, 655-663 565-596

6E SS 1898 333-335, 370-372 598-603

6F (18.7 sf) SS 1900 260-261 604-605

6G (18.6 sf) Alco 1901 262-259 606-613

6H (18) NR 1901 278-286, 541-552 614-634

6J (18) NR 1902 155, 160, 287-294, 537-540 635-648

6K (19 sf) Baldwin 1901 301-305, 795-799 649-658

(See Locobase 12447)

6L (18.7) NR 1904 909-910 659-660


Class 6G (Locobase 16126)

South African Railways & Harbours 9 -1941 Locomotive Diagrams supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 5646-5653 in December 1900.

As with the ten Baldwin Ten-wheelers supplied at the same time (Locobase 12448), these engines were designed by the builder to the requirements laid out by the CGR. Apparently because these were North American designs, they were inevitably bigger than all of the British-built Class 6s already in service. Even the cylinders measured 1/2" more in diameter.

Yet, the Schenectady's were not as big as the Baldwin 6Ks. Their grate areas were identical but the 6Gs had less firebox heating surface area, shorter (and 3 fewer) firetubes, and they weighed less. Their profiles declared their North American roots in a pleasing profile.

The design obviously suited the SAR, if the class's longevity is any guide.The last was not retired in


Class 6J (Locobase 11255)

Data from "Cape Government Railways," The Locomotive Magazine, Vol V (July 1900), p. 105. Additional information from the South African Railways historical website [], last accessed 15 May 2010.

The main entry on the 6 class can be found at Locobase 10153. This entry contains the data held on an SAR diagram for the 6J class. Compared to the earlier Class 6 engines, the 6J's boiler had 3 fewer tubes, each of which had a greater diameter and thus added up to somewhat greater heating surface area. Also, the boiler pressure was rated 20% higher.


Class 6K (Locobase 12448)

Data from DeGolyer, Volume 23, p. 137. Works numbers were 18319-18322, 18348-18353 in October 1900.

(NB: Road numbers for the CGR didn't quite run consecutively. Instead the sequence (in works number order) ran 301-303, 796, 798, 797, 799, 795, 304-305. For some reason, the SAR didn't rationalize the order when they nationalized the CGR. The new series order was: 649-651, 655, 657, 656, 658, 654, 652-653.)

Baldwin's only contribution to the varied and numerous Class 6 Ten-wheeler series consisted of some of the biggest in the group. Not only was the boiler larger, but also cylinder volume grew and steam pressure increased.

Survival in SAR service seems to have depended on where the locomotives operated. The 6Ks operated on the East London main line and were retired by 1928.


Class B/NG8 (Locobase 988)

See"Narrow Gauge Locomotive, Cape Government Railways," The Locomotive Magazine, Volume XII [12] (14 April 1906), p. 59; and "South African Class NG8 4-6-0" in Wikipedia at [], last accessed 26 June 2023. Works numbers were 1741-1746 in May-August 1904.and 1967 in 1913.

The design was credited to "Messrs. Gregory & Eyles, Sir Douglas Fox & Partners, and Sir Charles Metcalfe, Bart."

These were NG7 2-6-0s (Locobase 984) with a four-wheel leading truck. Running on the Langkloof line between Port Elizabeth and Avontuur, they "became the mainstay of motive power on the Avontuur branch," according to Wikipedia. Sometimes engines would be sent to the Kalbaskraal branch running toward Saldanha.

On such a skinny gauge, the locomotive's top speed of 30 mph (48 kph) suggested celerity and could pull 100 tons up a 2 1/2% grade.

Withdrawn in late 1920 except for NG27, which was sold to the Eastern Province Cement Company to use it to haul limestone on its industrial line from New Brighton in Port Elizabeth. Avontuur branch at Chelsea Junction.[1]

NB: Tube length is an estimate based on the calculation of tube surface area by subtracting reported firebox heating surface from reported total evaporative heating surface


Class Improved B/NG8 (Locobase 991)

Data from "South African Class NG8 4-6-0" in Wikipedia at [], last accessed 26 June 2023. Bagnall works number was 1967 in 1914. Kerr, Stuart works were 1345-1346 in September 1914.

More than a decade after the delivery of six Bagnall-built Pacific tanks that were based on Baldwin's NG7 2-6-0 (Locobase 984), but with a four-wheel leading truck. It had the same outside frame as the Baldwin as well as a bar frame and copper firebox.

All were withdrawn by 1931.


Class NG9 (Locobase 985)

Data from DeGolyer, Volume 63, pp.76+; and d Dave Richardson "Last Survivor set to steam again" on UK-based narrow gauge forum at [] . Baldwin works numbers ran in a series: 42301-42306 in August 1915.

Appear to be NG7 2-6-0s with a four-wheel leading truck and duplicated six Bagnall-built engines of 1903. Like the Bagnalls, this set had frames outside the wheels. The specifications called for the engines to be capable of negotiating a 44 1/2 degree curve (radii of 132 feet/40.2 metres) at a minimum speed of 8 mph (12.9 kph) while climbing a 2.8% grade.

But Dave Richardson wrote that these little Ten-wheelers couldn't reverse at speeds more than 10 mph (16 kph).

Note that the loaded tender weighed a bit more than the loaded locomotive.

Three sold to Angola Rwys, others withdrawn in late 1920s.

Principal Dimensions by Steve Llanso of Middle Run Media

Class6B/6C6C - Belpaire6C - Belpaire-superheated6D/6H6G
Locobase ID16122 16124 16125 10153 16126
RailroadCape Government Railways (SAR)Cape Government Railways (SAR)Cape Government Railways (SAR)Cape Government Railways (SAR)Cape Government Railways (SAR)
CountrySouth AfricaSouth AfricaSouth AfricaSouth AfricaSouth Africa
Whyte4-6-04-6-04-6-04-6-04-6-0
Number in Class75528
Road Numbers490-564/234-269 etc/565-596, 614-634262-269/606-613
Gauge3'6"3'6"3'6"3'6"3'6"
Number Built75528
BuilderseveralSARSARseveralSchenectady
Year189618981900
Valve GearStephensonStephensonStephensonStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)11 / 3.3511 / 3.3511 / 3.3511.33 / 3.4511.33 / 3.45
Engine Wheelbase (ft / m)20.31 / 6.1920.31 / 6.1920.31 / 6.1920.67 / 6.3021.17 / 6.45
Ratio of driving wheelbase to overall engine wheelbase 0.54 0.54 0.54 0.55 0.54
Overall Wheelbase (engine & tender) (ft / m)46.51 / 14.1842.05 / 12.8242.05 / 12.8244.98 / 13.71
Axle Loading (Maximum Weight per Axle) (lbs / kg)27,216 / 12,34530,016 / 13,61530,016 / 13,61528,000 / 12,70128,560 / 12,955
Weight on Drivers (lbs / kg)77,056 / 34,95290,048 / 40,84590,048 / 40,84582,768 / 37,54381,800 / 37,104
Engine Weight (lbs / kg)103,600 / 46,992114,464 / 51,920114,464 / 51,920107,856 / 48,923108,700 / 49,306
Tender Loaded Weight (lbs / kg)76,384 / 34,64776,384 / 34,64776,384 / 34,64774,144 / 33,631
Total Engine and Tender Weight (lbs / kg)179,984 / 81,639190,848 / 86,567190,848 / 86,567182,844 / 82,937
Tender Water Capacity (gals / ML)3120 / 11.823120 / 11.823120 / 11.822928 / 11.093360 / 12.73
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 6.05 / 6 8.25 / 8 8.25 / 8 6.60 / 6
Minimum weight of rail (calculated) (lb/yd / kg/m)43 / 21.5050 / 2550 / 2546 / 2345 / 22.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)54 / 137254 / 137254 / 137254 / 137254 / 1372
Boiler Pressure (psi / kPa)160 / 11180 / 12.40180 / 12.40150 / 10.30180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)17" x 26" / 432x66017" x 26" / 432x66017" x 26" / 432x66017" x 26" / 432x66017.5" x 26" / 445x660
Tractive Effort (lbs / kg)18,924 / 8583.7921,290 / 9656.9921,290 / 9656.9917,741 / 8047.1922,560 / 10233.06
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.07 4.23 4.23 4.67 3.63
Heating Ability
Tubes (number - dia) (in / mm)185 - 1.875" / 48220 - 2" / 51109 - 2" / 51185 - 1.875" / 48195 - 2" / 51
Flues (number - dia) (in / mm)18 - 5.5" / 140
Flue/Tube length (ft / m)11.18 / 3.4111.19 / 3.4111.19 / 3.4111.1811.35 / 3.46
Firebox Area (sq ft / m2)101 / 9.38111 / 10.31111 / 10.31107 / 9.94112 / 10.41
Grate Area (sq ft / m2)16.62 / 1.5417 / 1.5817 / 1.5818 / 1.6719 / 1.77
Evaporative Heating Surface (sq ft / m2)1116 / 103.681399 / 129.971039 / 96.531122 / 104.281267 / 117.71
Superheating Surface (sq ft / m2)211 / 19.60
Combined Heating Surface (sq ft / m2)1116 / 103.681399 / 129.971250 / 116.131122 / 104.281267 / 117.71
Evaporative Heating Surface/Cylinder Volume163.39204.82152.11164.27175.05
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation26593060306027003420
Same as above plus superheater percentage26593060358027003420
Same as above but substitute firebox area for grate area16,16019,98023,37716,05020,160
Power L134174634828432754089
Power MT293.29340.36608.44261.70330.61

Principal Dimensions by Steve Llanso of Middle Run Media

Class6J6KB/NG8Improved B/NG8NG9
Locobase ID11255 12448 988 991 985
RailroadCape Government Railways (SAR)Cape Government Railways (SAR)Cape Government (SAR)Cape Government (SAR)South African Railways (SAR)
CountrySouth AfricaSouth AfricaSouth AfricaSouth AfricaSouth Africa
Whyte4-6-04-6-04-6-04-6-04-6-0
Number in Class1810626
Road Numbers155, 160, 287-294, 537-540/635-648301-305, 795-799 / 649-658NG33-38/NG27-32NG36-38NG42-NG47
Gauge3'6"3'6"2'2'2'
Number Built1810626
BuilderNeilson, ReidBurnham, Williams & CoWG BagnallseveralBaldwin
Year19021900190419141915
Valve GearStephensonStephensonStephensonWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)11.33 / 3.4511.67 / 3.56 6.50 / 1.98 6.25 6.25 / 1.90
Engine Wheelbase (ft / m)20.67 / 6.3021.33 / 6.5010 / 3.0513.0813.08 / 3.99
Ratio of driving wheelbase to overall engine wheelbase 0.55 0.55 0.65 0.48 0.48
Overall Wheelbase (engine & tender) (ft / m)45.71 / 13.9336.87 / 11.24
Axle Loading (Maximum Weight per Axle) (lbs / kg)29,920 / 13,57112,800 / 5806
Weight on Drivers (lbs / kg)82,768 / 37,54385,000 / 38,55537,520 / 17,01937,408 / 16,96838,000 / 17,237
Engine Weight (lbs / kg)104,832 / 47,551107,000 / 48,53445,360 / 20,57545,472 / 20,62645,400 / 20,593
Tender Loaded Weight (lbs / kg)74,000 / 33,56642,560 / 19,30546,592 / 21,13446,400 / 21,047
Total Engine and Tender Weight (lbs / kg)181,000 / 82,10087,920 / 39,88092,064 / 41,76091,800 / 41,640
Tender Water Capacity (gals / ML)3600 / 13.643360 / 12.731800 / 6.821800 / 6.82
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)11 / 10 5.50 / 5 5.50 / 5
Minimum weight of rail (calculated) (lb/yd / kg/m)46 / 2347 / 23.5021 / 10.5021 / 10.5021 / 10.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)54 / 137254 / 137233 / 83833 / 83833 / 838
Boiler Pressure (psi / kPa)170 / 11.70180 / 10.30180 / 12.40180 / 12.40180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)17" x 26" / 432x66017.5" x 26" / 445x66011.75" x 16" / 298x40611.75" x 16" / 298x40611.75" x 16" / 298x406
Tractive Effort (lbs / kg)20,107 / 9120.3922,560 / 10233.0610,242 / 4645.7010,242 / 4645.7010,242 / 4645.70
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.12 3.77 3.66 3.65 3.71
Heating Ability
Tubes (number - dia) (in / mm)182 - 2" / 51192 - 2" / 5168 - 2" / 5168 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)11.18 / 3.4112 / 3.6610.75 / 3.2810.79 / 3.29
Firebox Area (sq ft / m2)108 / 10.04120.50 / 11.2040.47 / 3.7640.50 / 3.7643 / 3.99
Grate Area (sq ft / m2)19 / 1.7719 / 1.77 7.60 / 0.71 7.60 / 0.71 7.50 / 0.70
Evaporative Heating Surface (sq ft / m2)1173 / 109.011315 / 122.21421 / 39.11421 / 39.11424 / 39.39
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1173 / 109.011315 / 122.21421 / 39.11421 / 39.11424 / 39.39
Evaporative Heating Surface/Cylinder Volume171.73181.68209.66209.66211.15
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation32303420136813681350
Same as above plus superheater percentage32303420136813681350
Same as above but substitute firebox area for grate area18,36021,690728572907740
Power L138374292307330743150
Power MT306.61333.96541.69543.49548.25

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