South African Class 6E1, Series 2

South African Class 6E1, Series 2
No. E1252 at Sentrarand, Gauteng, 29 September 2009
Type and origin
Power type	Electric
Designer	Union Carriage and Wagon
Builder	Union Carriage and Wagon
Model	UCW 6E1
Build date	1971
Total produced	50
Specifications
UIC classification	Bo-Bo
Gauge	3 ft 6 in (1,067 mm) Cape gauge
Bogies	3.430 m (11 ft 3 in) wheelbase
Wheel diameter	1,220 mm (48 in)
Wheelbase	11.279 m (37 ft 0.1 in)
Length	15.494 m (50 ft 10 in)
Width	2.896 m (9 ft 6 in)
Height	4.089 m (13 ft 5 in) pantographs down
Axle load	22,226 kg (21.9 long tons)
Locomotive weight	88,904 kg (87.5 long tons)
Current collection method	Pantographs
Traction motors	Four AEI 283 AZ
Transmission	18/67 gear ratio
Performance figures
Maximum speed	113 km/h (70 mph)
Power output	Per motor: 623 kW (835 hp) 1 hour 563 kW (755 hp) continuous Total: 2,492 kW (3,342 hp) 1 hour 2,252 kW (3,020 hp) continuous
Tractive effort	311 kN (70,000 lbf) starting 221 kN (50,000 lbf) 1 hour 193 kN (43,000 lbf) continuous at 40 km/h (25 mph)
Locomotive brake	Air & Regenerative
Train brakes	Air & Vacuum
Career
Operator(s)	South African Railways Spoornet Transnet Freight Rail
Class	Class 6E1
Power class	3 kV DC
Number in class	50
Number(s)	E1246-E1295 [1]
Delivered	1971
First run	1971

The South African Class 6E1, Series 2 of 1971 is a South African electric locomotive from the South African Railways era.

In 1971 the South African Railways placed fifty Class 6E1, Series 2 electric locomotives with a Bo-Bo wheel arrangement in mainline service. Series 2 was the first of the Class 6E1s to have their sandboxes mounted along the bottom edge of the locomotive body sides.^[1]

Manufacturer

The 3 kV DC Class 6E1, Series 2 electric locomotive was designed and built for the South African Railways (SAR) in 1971 by Union Carriage and Wagon (UCW) in Nigel, Transvaal, with the electrical equipment supplied by the General Electric Company (GEC). Fifty locomotives were delivered in 1971, numbered in the range from E1246 to E1295.^[2]

UCW did not allocate works numbers to the locomotives it built for the SAR and used the SAR unit numbers for their record keeping.^[1]

Characteristics

Bogies

The Class 6E1 was built with sophisticated traction linkages on their bogies and with stabilisers mounted between the linkages on the bogies and the locomotive body. Together with its electronic wheelslip detection system, these traction linkages and stabilisers ensure the maximum transfer of power to the rails without causing wheelslip.^[3]

Orientation

These dual cab locomotives have a roof access ladder on one side only, just to the right of the cab access door. The roof access ladder end is marked as the number 2 end. A passage along the centre of the locomotive connects the cabs, which are identical apart from the fact that the handbrake is located in cab 2. A pantograph hook stick is stowed in a tube mounted below the lower edge of the locomotive body on the roof access ladder side. The locomotive has three small panels along the lower half of the body on the roof access ladder side, and only one panel on the opposite side.^[1]

Series identifying features

The Class 6E1 was produced in eleven series over a period of nearly sixteen years, with altogether nine hundred and sixty units placed in service, all built by UCW. This makes the Class 6E1 the most numerous single locomotive class ever to have seen service in South Africa and serves as ample proof of a highly successful design.^[1][3]

While some Class 6E1 series are visually indistinguishable from their predecessors or successors, some externally visible changes did occur over the years. Series 1 locomotives had their sandboxes mounted on the bogies, while Series 2 to 11 had their sandboxes mounted along the bottom edge of the locomotive body, with the sandbox lids fitting into recesses in the body.^[1]

The fifty Series 2 and the first fifty Series 3 locomotives are visually indistinguishable from each other. On the Series 3 locomotives in the number range from E1346 to E1445, an externally visible difference is a wider stirrup middle step below their side doors. This appears to indicate that Series 2 should actually have consisted of one hundred locomotives and not fifty, firstly since these locomotives, numbers E1246 to E1345, are identical in exterior appearance, and secondly since Series 4, 5 and 6 were all delivered in batches of one hundred.^[1][4][5]

Had that been the case, Series 2 and 3 would also have consisted of one hundred locomotives each, numbers E1246 to E1345 and E1346 to E1445 respectively, instead of fifty and one hundred and fifty as they were officially designated, numbered E1246 to E1295 and E1296 to E1445 respectively.^[4][5]

Operation

Startup

When there is no compressed air in the locomotive's system to raise a pantograph to start up, a pantograph hook stick is used to manually raise the pantograph. This starts the high voltage motor that drives the auxiliary alternator to supply 110V power to start the compressor and power other control circuits. Once there is enough main air pressure to keep the pantograph in the raised position, the pantograph hook stick can be dropped.^[6]

The locomotive is controlled via resistors over which the voltage is dropped in a configuration of series and parallel electrical circuits. The circuit breakers that switch these circuits work under very high power and voltage and are therefore all pneumatically operated for insulation purposes. Compressed air is required to open or close the switch actions and air is also used for the weakfield cam switch, which also switches under very high currents.^[6]

Running

Upon starting off and in the low notches the major part of the voltage is dropped over the banks of resistors and all four traction motors are in series.^[6] The blowers that accelerate the dissipation of heat in the resistor banks give the Class 6E its very distinctive sound, a deep and loud whine when power is applied.^[7]

As the driver notches up, some of the resistor banks are cut out via the pneumatically operated switches and the voltage increases across the traction motors. The more resistors that are cut out as the driver notches higher, the more power is developed by the traction motors. At around 22 to 28 kilometres per hour (14 to 17 miles per hour) the locomotive switches to a parallel combination, where the two traction motors per bogie are in a series electrical circuit while the two bogies are in parallel electrical circuit. Eventually, when all resistors are cut out, the locomotive is operating in full-field.^[6]

When the traction motors are operated in full-field, be it in series or parallel mode, they are performing at maximum power for normal operation. To increase the speed at this point, if necessary, higher power output is required from the traction motors. The only way to increase power is to force a higher current flow. To accomplish this, the weakfield cam switch switches resistance in parallel with the field coils, which reduces the overall resistance of the field coils. This increases the magnetic flux and more power is generated by the traction motors over short periods.^[6]

Brakes

The locomotive itself used air brakes, but it was equipped to operate trains with air or vacuum brakes. The brake system would be set up for either air or vacuum train working by means of a turning switch on the driver's brake valve and by pre-setting the appropriate brake valves in the passage.

The Class 6E1 locomotives were built with an air brake system consisting of various valves connected to each other with pipes, commonly referred to as a “bicycle frame” brake system. The compressed air pipes run under the locomotive's belly in a zig-zag pattern, going through bolster and other members to extend its length to allow the maximum amount of moisture to condense on the way to the reservoirs. As a result it has multiple pipe connections. A weakness of the system was that, after an accident or even a hard coupling, these pipes tended to develop leaks at the joints that were extremely difficult to repair.^[8]

While hauling a vacuum braked train, the locomotive's air brake system would be disabled and the train would be controlled using the train brakes alone to slow down and stop. While hauling an air braked train, on the other hand, the locomotive brakes would engage along with the train brakes. While working either type of train downgrade, the locomotive's regenerative braking system would also work in conjunction with the train brakes.

When the locomotive was stopped, the air brakes on both bogies were applied together. The handbrake or parking brake, located in Cab no. 2, only operated on the unit's last axle, or no. 7 and 8 wheels.

Service

The Class 6E1 family saw service all over both of the 3 kV DC mainline and branchline networks, the smaller Cape Western network between Cape Town and Beaufort West and the larger network that covers portions of the Northern Cape, the Free State, Natal, Gauteng, North West Province and Mpumalanga.^[9]

Reclassification and rebuilding

Reclassification to Class 16E

During 1990 and 1991 Spoornet semi-permanently coupled several pairs of otherwise largely unmodified Class 6E1 locomotives, reclassified them to Class 16E and allocated a single locomotive number to each pair, with the individual locomotives in the pairs inscribed "A" or "B". The aim was to accomplish savings on cab maintenance by coupling the locomotives at their number 1 ends, abandoning the number one end cabs in terms of maintenance and using only the number two end cabs.^[9]

One such pair was made up of two Series 2 locomotives, numbers E1272 and E1273, which became Class 16E number 16-100A and B respectively.^[9]

Rebuilding to Class 18E

Beginning in 2000, Spoornet began a project to rebuild Series 2 to 11 Class 6E1 locomotives to Class 18E, Series 1 and Series 2 at the Transnet Rail Engineering (TRE) workshops at Koedoespoort. In the process the cab at the number 1 end was stripped of all controls in order to have a toilet installed, thereby forfeiting the loco's bi-directional ability. Since the driving cab's noise level had to be below 85 decibels, cab 2 was selected as the Class 18E driving cab primarily based on its lower noise level compared to cab 1, which is closer and more exposed to the compressor's noise and vibration. Another factor was the closer proximity of cab 2 to the low voltage switch panel. The fact that the handbrake was located in cab 2 was not a deciding factor, but was considered an additional benefit.^[9][10]

The known Class 6E1, Series 2 locomotives that were used in this project were all rebuilt to Class 18E, Series 2 locomotives. Their numbers and renumbering details are shown in the table.^[10]

Class 6E1, Series 2 units rebuilt to Class 18E
as on 19 January 2015

Count	6E1 no.	Year built	18E no.	18E series	Year rebuilt	Notes
1	E1259	1971	18-426	2	2013	PRASA
2	E1261	1971	18-824	2		Uncompleted
3	E1265	1971	18-752	2	2013
4	E1268	1971	18-751	2	2013
5	E1277	1971	18-801	2	2014	c. 2014

Liveries illustrated

The main picture shows number E1252 in Spoornet orange livery at Sentrarand locomotive depot in Gauteng. Illustrated below are some of the other liveries that Series 2 locomotives served in.

• 

  No. E1267 in Spoornet’s lined orange livery at Capital Park Depot, Pretoria, 10 May 2013

• 

  No. E1289 in Spoornet blue livery with outline numbers at Bayhead Depot, Durban, 11 August 2007

See also

• Electric locomotive numbering and classification
• List of South African locomotive classes
• South African Class 6E1, Series 1
• South African Class 6E1, Series 3
• South African Class 6E1, Series 4
• South African Class 6E1, Series 5
• South African Class 6E1, Series 6
• South African Class 6E1, Series 7
• South African Class 6E1, Series 8
• South African Class 6E1, Series 9
• South African Class 6E1, Series 10
• South African Class 6E1, Series 11
• South African Class 18E, Series 2
• South African locomotive history

References

Wikimedia Commons has media related to: South African Class 6E1 Series 2

Locomotives of South Africa Steam Brunel gauge HBEL 0-4-0 HBTB 0-4-0T HBTB 0-4-0WT HBTB 0-4-0ST Broad gauge CGR Aid CGR Blackie CGR 0-4-2 CGR 2-4-0T NRC Durban NRC Natal NRC Perseverance Cape gauge Tank CGR Coffee Pot CGR 040 1873 CGR 040 1874 CGR 060 1876 CGR 060 1902 CGR 260 1900 CGR 260 1902 CGR 1st 040 1875 CGR 1st 440 1875 CGR 1st 040 1876 CGR 1st 260 1876 CGR 2nd 1882 CGR 3rd 1900 CGR RM CSAR C CSAR E CSAR Rack CSAR RM Dbn Congella Dbn Edward Innes Dbn John Milne Dbn Sir Albert HBPE 040 Kowie 060 Kowie 440 M&S 462 NGR Dbn & Pmb NGR I 262 NGR K 040 NGR K 060 NGR K 260 NZASM 10T NZASM 14T NZASM 18T NZASM 19T NZASM 32T NZASM 40T PPR 26T PPR 35T SAR RM SAR 0-4-0ST SAR 040 69 SAR A SAR B SAR C SAR C1 SAR C2 SAR D SAR E SAR F SAR G SAR H SAR H1 SAR H2 SAR J SAR K SWA 2-8-0T Cape gauge Tender CGR 1st 260 1876 BP CGR 1st 260 1876 K CGR 1st 260 1879 CGR 1st 440 1879 CGR 1st 1881 CGR 1st 1891 CGR 2nd 1875 CGR 3rd 1883 CGR 3rd 1884 CGR 3rd 1889 CGR 3rd 1898 CGR 3rd 1901 CGR 3rd 1903 CGR 4th 1880 CGR 4th 1882 CGR 4th 1884 CGR 4th 1897 CGR 5th 1890 CGR 5th 1891 NGR Havelock NGR I 260 Exp-1 Exp-2 Exp-3 Exp-4 Exp-5 Exp-6 SAR S SAR S1 SAR S2 SAR 1 SAR 1A SAR 1B SAR 2 SAR 2C SAR 3 SAR 3A SAR 3B SAR 4 SAR 4A SAR 5 SAR 5A SAR 5B SAR 6 SAR 6A SAR 6B SAR 6C SAR 6D SAR 6E SAR 6F SAR 6G SAR 6H SAR 6J SAR 6K SAR 6L SAR 6Y SAR 6Z SAR 7 SAR 7A SAR 7B SAR 7C SAR 7D SAR 7E SAR 7F SAR 8 SAR 8A SAR 8B SAR 8C SAR 8D SAR 8E SAR 8F SAR 8X SAR 8Y SAR 8Z SAR 9 SAR 10 SAR 10A SAR 10B SAR 10C SAR 10D SAR 11 SAR 12 SAR 12A SAR 12B SAR 13 SAR 14 SAR 14A SAR 14B SAR 14C SAR 15 SAR 15A SAR 15B SAR 15C SAR 15CA SAR 15E SAR 15F SAR 16 SAR 16A SAR 16B SAR 16C SAR 16D SAR 16DA SAR 16E SAR 17 SAR 18 SAR 19 SAR 19A SAR 19B SAR 19C SAR 19D SAR 20 SAR 21 SAR 23 SAR 24 SAR 25 SAR 25NC SAR 26 SWA 2-8-0 Cape gauge Articulated CGR Fairlie CGR Kitson-Meyer SAR FC SAR FD SAR GA SAR GB SAR GC SAR GCA SAR GD SAR GDA SAR GE SAR GEA SAR GF SAR GG SAR GH SAR GK SAR GL SAR GM SAR GMA SAR GO SAR HF SAR KM SAR MA SAR MB SAR MC SAR MC1 SAR MD SAR ME SAR MF SAR MG SAR MH SAR MJ SAR MJ1 SAR U 2ft 6in gauge CCC 1871 CCC Britannia CCC Caledonia CCC Clara CCC Condenser CCC Scotia NCC Pioneer 2ft & 600mm gauges ACR NG-G16A CGR NG 060 CGR NG 462 CGR A CGR C NGR N SAR 040 1899 SAR NG1 SAR NG2 SAR NG3 SAR NG4 SAR NG5 SAR NG6 SAR NG7 SAR NG8 SAR NG9 SAR NG10 SAR NG-G11 SAR NG-G12 SAR NG-G13 SAR NG-G14 SAR NG15 SAR NG-G16 SWA Ha SWA Hb SWA Hc SWA Hd SWA Jung SWA Zwillinge Diesel -electric SAR DS SAR DS1 SAR 31-000 SAR 32-000 SAR 32-200 SAR 33-000 SAR 33-200 SAR 33-400 SAR 34-000 SAR 34-200 SAR 34-400 SAR 34-500 SAR 34-600 SAR 34-800 SAR 34-900 SAR 35-000 SAR 35-200 SAR 35-400 SAR 35-600 SAR 36-000 SAR 36-200 SAR 37-000 SN 39-000 TFR 39-200 TFR 43-000 SAR 91-000 Afro4000 -hydraulic SAR 61-000 Electro-diesel SN 38-000 Electric SAR ES SAR ES1 Exp-AC SAR 1E SAR 2E SAR 3E SAR 4E SAR 5E-S1 SAR 5E-S2 SAR 5E-S3 SAR 5E1-S1 SAR 5E1-S2 SAR 5E1-S3 SAR 5E1-S4 SAR 5E1-S5 SAR 6E SAR 6E1-S1 SAR 6E1-S2 SAR 6E1-S3 SAR 6E1-S4 SAR 6E1-S5 SAR 6E1-S6 SAR 6E1-S7 SAR 6E1-S8 SAR 6E1-S9 SAR 6E1-S10 SAR 6E1-S11 SAR 7E SAR 7E1 SAR 7E2-S1 SAR 7E2-S2 SAR 7E3-S1 SAR 7E3-S2 SN 7E4 SAR 8E SAR 9E-S1 SAR 9E-S2 SAR 10E SAR 10E1-S1 SAR 10E1-S2 SAR 10E2 SAR 11E SAR 12E SN 14E SN 14E1 TFR 15E SN 16E SN 17E SN 18E-S1 TFR 18E-S2 TFR 19E TFR 20E TFR 21E E38 List of South African locomotive classes Rail transport in South Africa