South African Class 21E

No. 21-010 at Koedoespoort, 29 September 2015

Type and origin
Power type	Electric
Designer	Zhuzhou Electric Locomotive Co.
Builder	Zhuzhou Electric Locomotive Co. Transnet Engineering
Model	ZELC 21E
Build date	2014-2015
Total produced	100

Specifications
Configuration:
• AAR	B-B
• UIC	Bo'Bo'
• Commonwealth	Bo-Bo
Gauge	3 ft 6 in (1,067 mm) Cape gauge
Axle load	26,000 kg (57,000 lb)
Electric system/s	Dual 3 kV DC & 25 kV AC/50 Hz catenary
Current pickup(s)	Pantographs
Traction motors	Four
MU working	8 units
Loco brake	Electro-pneumatic, regenerative & rheostatic
Train brakes	Air
Couplers	AAR knuckle Type F

Performance figures
Maximum speed	100 km/h (62 mph)
Power output	3,000 kW (4,000 hp)

Career
Operators	Transnet Freight Rail
Class	21E
Number in class	100
Numbers	21-001 to 21-100
Delivered	2014-2015
First run	2014

The Transnet Freight Rail Class 21E of 2014 is a South African electric locomotive.

On 16 September 2014, the first of the Class 21E dual voltage electric locomotives for Transnet Freight Rail was rolled out at the CSR Zhuzhou Electric Locomotive Company in China. Two of these locomotives were built in China with another 38 to follow, while the rest were built in South Africa.^[1]^[2]^[3]

Manufacturer

The first forty of the one hundred 3 kV DC and 25 kV AC dual voltage Class 21E electric locomotives for Transnet Freight Rail were built in China by Zhuzhou Electric Locomotive Company, a subsidiary of the China South Locomotive and Rolling Stock Corporation (CSR), China's leading train manufacturer.^[1]

The roll-out ceremony of the first locomotive, no. 21-001, took place at the factory on 16 September 2014. The remaining sixty locomotives of the order were built in South Africa.^[2]^[3]^[4]

According to the project plan, the agreement also included the joint production of more electric locomotives, electric multiple units, suburban rail vehicles and rail transportation equipment for South Africa and the African region.^[1]^[2]^[3]^[4]

The first two locomotives were delivered for acceptance trials on 11 December 2014. They came ashore at Maydon Wharf in Durban and were moved dead in tow to Pyramid South Depot, north of Pretoria, the following day. No. 21-002 was equipped with load-measuring-wheelsets, painted yellow, on its front bogie.

Characteristics

The Class 21E is virtually identical in visual appearance to the earlier Class 20E locomotive, which was described by the manufacturer as the "promotion version" of the Class 21E. It is, in essence, an upgraded version of the Class 20E based on customer requirements. It is a heavier locomotive, with the axle load increased to 26,000 kilograms (57,000 pounds) and with improved tractive effort to make it more suitable for service on the Coalink line. It makes use of more advanced electronically controlled pneumatic (ECP) brake system technology to control the train's air brakes through electrical signals, which improves the train's braking response time and results in improved safety and reliability. The four-axle locomotive is capable of an output of 3,000 kilowatts (4,000 horsepower) and a speed of 100 kilometres per hour (62 miles per hour). Its microcomputer network control system allows eight of these locomotives to work together in a multi-unit consist and also to work consisted to diesel-electric locomotives.^[1]^[2]^[3]

The only externally visible differences between the Classes 20E and 21E are on the end sills, buffer beams, cowcatchers and the left side of the cab roof.

The Class 20E has two cable sockets on each side of the coupler and a fifth socket in a cut-out on the sill, below the front door on the front sill and in the same position on the rear sill, near the right end of the sill. The Class 21E has no such cut-out in the sill. The radio frequency distributed power (RFDP) conjunction boxes are mounted below the sockets to the right hand side of the coupler.
The Class 21E has a small rectangular grille near the rear end of the left side of the cab roof, above the large grilled hatch door to the right of the cab door on the left side. This small grille is absent on the Class 20E.^[5]

Layout

The locomotive body is a welded monocoque design, constructed of steel plates and profiled members, which has a compressive strength of 4.45 meganewtons (1,000,000 pounds-force) and a tensile strength of 4 meganewtons (900,000 pounds-force). The Class 21E has a single cab and a gangway along the centre of the locomotive. It is equipped with a wireless data transmission system which can send the locomotive operation status, fault data and energy consumption data via GSM and Wi-Fi to a trackside station for analysis. It is also equipped with an axle temperature alarm device, fire alarm system, closed-circuit television (CCTV) system, wheel flange lubricating device and, as personnel safety measure, high voltage protective interlocking devices. The AC traction motors are powered through insulated-gate bipolar transistor (IGBT) control.^[6]

Dual voltage

As on the dual voltage Classes 19E and 20E, the main electric circuit is automatically selected in either AC or DC mode, based on the voltage of the overhead contact wire feeding the locomotive. To facilitate automatic trouble-free transition on the run, the locomotive is equipped with onboard voltage detectors, while the overhead wire is equipped with two wooden isolators and a 3 metres (10 feet) length of neutral wire to separate the AC and DC feeds. The neutral section is connected to the rails, which serve as the return conductor on electrified lines.^[6]

The transition process requires that the locomotive should automatically be switched off before it reaches the isolators and the unpowered overhead wire section, and automatically be restarted after exiting from under the unpowered wire. This is done by a pair of track magnets, one on either side of the neutral overhead wire and spaced 45 metres (148 feet) apart. The two magnets are mounted with their polarities reversed in relation to each other and they activate a magnetic relay located behind the cowcatcher of the locomotive to do the switching off and restarting.^[6]

Pantographs

Transnet Freight Rail insisted that the locomotive must be designed in such a way that the pantograph contact shoe centres are directly above the bogie pivot centres, as was done on the Class 7E and Class 7E2, Series 1 and Series 2 and again on the Class 20E. The reason is to reduce the possibility of pantograph hookups on catenary in sharp curves, such as in turnouts, as a result of sideways movement of the pantograph in relation to the overhead wire.^[6]^[7]

Service

The Class 21E was placed in service on the 25 kV AC Coalink line between Ermelo and the Richards Bay Coal Terminal.^[2]^[3] They work directly from the coal mines around Ermelo, running under 3 kV DC catenary. The dual voltage Class 21E locomotives can therefore haul their loads directly from the mines all the way to Richards Bay without having to change locomotives in Ermelo to cater for the change in the power supply.

Illustration

No. 21-040 at Koedoespoort, Pretoria on 29 September 2015
No. 21-004 at Koedoespoort, Pretoria on 29 September 2015
No. 21-003 at Koedoespoort, Pretoria on 29 September 2015
No. 21-033 at Koedoespoort, Pretoria on 29 September 2015

References

Wikimedia Commons has media related to South African Class 21E.

^ ^a ^b ^c ^d South Africa welcomed the new Chinese-made locomotives and then upgrade rail transportation equipment (As translated by TranStar, powered by Google Translate) - 18 September 2014 Archived 19 December 2014 at the Wayback Machine
^ ^a ^b ^c ^d ^e China South Locomotive and export electric locomotive off the assembly line in South Africa (As translated by TranStar, powered by Google Translate) - CSR Zhushou Electric Locomotive Co. Ltd., 17 September 2014
^ ^a ^b ^c ^d ^e South Africa rail transportation equipment to build an upgraded version of Chinese CSR Zhuzhou Locomotive successfully developed a new assembly line in South Africa (As translated by TranStar, powered by Google Translate) - African Times, published 17 September 2014
^ ^a ^b History in the Making - The Lowdown on the New 21E Locomotives. By Ayanda Mthethwa in Transnet Freight Rail Weekly News Bulletin 15, 21 December 2014
^ African Times photograph of no. 21-001
^ ^a ^b ^c ^d Class 20E manual: Part 1: Locomotive Profile and Technical Data
^ South African Railways Index and Diagrams Electric and Diesel Locomotives, 610mm and 1065mm Gauges, Ref LXD 14/1/100/20, 28 January 1975, as amended

Locomotives of South Africa

Steam

7' ¼" gauge	East London 0-4-0VB Table Bay 0-4-0ST Table Bay 0-4-0T Table Bay 0-4-0WT
Standard gauge	Cape 0-4-0T Blackie Cape 0-4-2 Cape 2-4-0T CGR 0-4-0ST Aid Natal 0-4-0ST Durban Natal 0-4-0WT Natal Natal 4-4-0T Perseverance
Cape gauge Tank engines	CGR 0-4-0ST 1873 CGR 0-4-0ST 1874 CGR 0-4-0ST 1881 CGR 0-4-0ST 1881 Coffee Pot CGR 0-6-0ST CGR 0-6-0T CGR 2-6-0ST 1900 CGR 2-6-0ST 1902 CGR 1st Class 0-4-0ST 1875 CGR 1st Class 0-4-0ST 1876 CGR 1st Class 2-6-0ST CGR 1st Class 4-4-0T CGR 2nd Class 4-4-0T CGR 3rd Class 2-6-0T CGR Railmotor CSAR Class C CSAR Class E CSAR Rack 4-6-4RT CSAR Railmotor Durban's Congella Durban's Edward Innes Durban's John Milne Durban's Sir Albert Port Elizabeth 0-4-0ST Kowie Railway 0-6-0T Kowie Railway 4-4-0T Metropolitan & Suburban 4-6-2T NGR 2-6-0T Durban & Pietermaritzburg NGR Class I 2-6-2T NGR Class K 0-4-0ST NGR Class K 0-6-0ST NGR Class K 2-6-0T NZASM 10 Tonner NZASM 13 Tonner NZASM 14 Tonner NZASM 18 Tonner NZASM 19 Tonner NZASM 32 Tonner NZASM 40 Tonner PPR 26 Tonner PPR 35 Tonner Portuguese SAR Class A SAR Class B SAR Class C SAR Class C1 SAR Class C2 SAR Class D SAR Class E SAR Class F SAR Class G SAR Class H SAR Class H1 SAR Class H2 SAR Class J SAR Class K SAR Railmotor SAR Dock 0-4-0ST SAR Dock 0-4-0T SWA 2-8-0T
Cape gauge Tender engines	CGR 1st Class 2-6-0 1876 BP CGR 1st Class 2-6-0 1876 Kitson CGR 1st Class 2-6-0 1879 CGR 1st Class 2-6-0 1891 CGR 1st Class 4-4-0 CGR 1st Class 4-4-0TT CGR 2nd Class 2-6-2TT CGR 3rd Class 4-4-0 1883 CGR 3rd Class 4-4-0 1884 CGR 3rd Class 4-4-0 1889 CGR 3rd Class 4-4-0 1898 CGR 3rd Class 4-4-0 1901 CGR 3rd Class 4-4-0 1903 CGR 4th Class 4-4-2 CGR 4th Class 4-6-0TT 1880 CGR 4th Class 4-6-0TT 1882 CGR 4th Class 4-6-0TT 1882 Joy CGR 4th Class 4-6-0TT 1884 CGR 5th Class 4-6-0 1890 CGR 5th Class 4-6-0 1891 NGR Havelock NGR Class I SAR Class Exp 1 SAR Class Exp 2 SAR Class Exp 3 SAR Class Exp 4 SAR Class Exp 5 SAR Class Exp 6 SAR Class S SAR Class S1 SAR Class S2 SAR Class 1 SAR Class 1A SAR Class 1B SAR Class 2 SAR Class 2C SAR Class 3 SAR Class 3A SAR Class 3B SAR Class 4 SAR Class 4A SAR Class 5 SAR Class 5A SAR Class 5B SAR Class 6 SAR Class 6A SAR Class 6B SAR Class 6C SAR Class 6D SAR Class 6E SAR Class 6F SAR Class 6G SAR Class 6H SAR Class 6J SAR Class 6K SAR Class 6L SAR Class 6Y SAR Class 6Z SAR Class 7 SAR Class 7A SAR Class 7B SAR Class 7C SAR Class 7D SAR Class 7E SAR Class 7F SAR Class 8 SAR Class 8A SAR Class 8B SAR Class 8C SAR Class 8D SAR Class 8E SAR Class 8F SAR Class 8R SAR Class 8X SAR Class 8Y SAR Class 8Z SAR Class 9 SAR Class 10 SAR Class 10A SAR Class 10B SAR Class 10C SAR Class 10D SAR Class 11 SAR Class 12 SAR Class 12A SAR Class 12B SAR Class 13 SAR Class 14 SAR Class 14A SAR Class 14B SAR Class 14C 1st SAR Class 14C 2nd SAR Class 14C 3rd SAR Class 14C 4th SAR Class 15 SAR Class 15A SAR Class 15B SAR Class 15C SAR Class 15CA SAR Class 15E SAR Class 15F SAR Class 16 SAR Class 16A SAR Class 16B SAR Class 16C SAR Class 16D SAR Class 16DA 1928 SAR Class 16DA 1930 SAR Class 16E SAR Class 17 SAR Class 18 SAR Class 19 SAR Class 19A SAR Class 19B SAR Class 19C SAR Class 19D SAR Class 20 SAR Class 21 SAR Class 23 SAR Class 24 SAR Class 25 SAR Class 25NC SAR Class 26 SAR Katanga SWA 2-8-0
Cape gauge Articulated engines	CGR Fairlie CGR Kitson-Meyer SAR Class FC SAR Class FD SAR Class GA SAR Class GB SAR Class GC SAR Class GCA SAR Class GD SAR Class GDA SAR Class GE SAR Class GEA SAR Class GF SAR Class GG SAR Class GH SAR Class GK SAR Class GL SAR Class GM SAR Class GMA SAR Class GO SAR Class HF SAR Class KM SAR Class MA SAR Class MB SAR Class MC SAR Class MC1 SAR Class MD SAR Class ME SAR Class MF SAR Class MG SAR Class MH SAR Class MJ SAR Class MJ1 SAR Class U
2' 6" gauge	Cape Copper John King & Miner Cape Copper Britannia Cape Copper Caledonia Cape Copper Clara Cape Copper Condenser Cape Copper Scotia Namaqua Copper Pioneer Walvis Bay 2-4-2T Hope
2' & 600mm gauges	ACR Class NG-G16A CGR NG 0-4-0T CGR NG 0-6-0T CGR NG 4-6-2T CGR Type A 2-6-4T CGR Type C 0-4-0T NGR Class N 4-6-2T SAR Dutton SAR NG 0-4-0T SAR Class NG1 SAR Class NG2 SAR Class NG3 SAR Class NG4 SAR Class NG5 SAR Class NG6 SAR Class NG7 SAR Class NG8 SAR Class NG9 SAR Class NG10 SAR Class NG-G11 SAR Class NG-G12 SAR Class NG-G13 SAR Class NG-G14 SAR Class NG15 SAR Class NG-G16 SWA Class Ha SWA Class Hb SWA Class Hc SWA Class Hd SWA Jung SWA Zwillinge

Electric

Amcoal Class E38

Gas-electric

SAR Gas-electric

Diesel

Cape gauge Diesel-electric	PRASA Class Afro 4000 SAR Class DS SAR Class DS1 SAR Class 31-000 SAR Class 32-000 SAR Class 32-200 SAR Class 33-000 SAR Class 33-200 SAR Class 33-400 SAR Class 34-000 SAR Class 34-200 SAR Class 34-400 SAR Class 34-500 SAR Class 34-600 SAR Class 34-800 SAR Class 34-900 SAR Class 35-000 SAR Class 35-200 SAR Class 35-400 SAR Class 35-600 TFR Class 35-800 SAR Class 36-000 SAR Class 36-200 SAR Class 37-000 Spoornet Class 39-000 TFR Class 39-200 TFR Class 43-000 TFR Class 44-000 TFR Class 45-000
2' gauge Diesel-electric	SAR Class 91-000
Cape gauge Diesel-hydraulic	SAR Class 61-000
Cape gauge Electro-diesel	Spoornet Class 38-000