{{Short description|1980 design of electric locomotive}} {{Use South African English|date=October 2013}} {{Use dmy dates|date=January 2024}} {{Infobox locomotive | name = South African Class 7E1 | image = SAR Class 7E1 E7111.JPG | alt = | caption = No. E7111 at [[Vryheid]], [[KwaZulu-Natal]], 16 August 2007 | hatnote = | powertype = Electric | designer = [[Hitachi]] | builder = Hitachi & [[DCD (company)|Dorbyl]] | ordernumber = | serialnumber = | buildmodel = Hitachi 7E1 | builddate = 1979-1981 | totalproduction = 50 | rebuilder = | rebuilddate = | numberrebuilt = | aarwheels = [[AAR wheel arrangement#C-C|C-C]] | uicclass = [[Co′Co′]] | Britishclass = [[Co-Co locomotives|Co-Co]] | gauge = {{Track gauge|Cape|allk=on}} | bogies = | leadingdiameter = | wheeldiameter = {{convert|1220|mm|in|2|abbr=on}} | trailingdiameter = | minimumcurve = | wheelbase = {{convert|13800|mm|ftin|frac=8|abbr=on}} | bogie = {{convert|4400|mm|ftin|frac=8|abbr=on}} | pivotcentres = {{convert|10200|mm|ftin|frac=8|abbr=on}} | pantoshoecentres = {{convert|11530|mm|ftin|frac=8|abbr=on}} | wheelspacing = | length = | over couplers = {{convert|18430|mm|ftin|frac=8|abbr=on}} | over bufferbeams = {{convert|17480|mm|ftin|frac=8|abbr=on}} | body = | width = {{convert|2906|mm|ftin|frac=8|abbr=on}} | height = | pantodown = {{convert|4180|mm|ftin|frac=8|abbr=on}} | bodyonly = {{convert|3941|mm|ftin|frac=8|abbr=on}} | frametype = | axleload = {{convert|21000|kg|lb|abbr=on}} | leadingbogie/pony= | weightondrivers = {{convert|125500|kg|lb|abbr=on}} | trail bogie/pony = | locoweight = {{convert|125500|kg|lb|abbr=on}} | sandcap = | electricsystem = [[25 kV AC]] 50 [[Hertz|Hz]] [[Overhead line|catenary]] | collectionmethod = [[Pantograph (transport)|Pantographs]] | alternator = | generator = | tractionmotors = Six HS-1054-GR | t/m amps 1 hr = {{convert|525|kW|hp|abbr=on}} | t/m amps cont = {{convert|500|kW|hp|abbr=on}} | headendpower = | transmission = | gear ratio = 16:94 | multipleworking = | trainheating = | locobrakes = [[Railway air brake|Air]] & [[Dynamic braking#Rheostatic braking|Rheostatic]] | trainbrakes = [[Railway air brake|Air]] & [[Vacuum brake|Vacuum]] | reservoircap = | compressorcap = | exhaustercap = | safety = | coupling = [[Janney coupler|AAR knuckle]] | maxspeed = {{convert|100|km/h|mph|abbr=on}} | poweroutput = | poweroutput start= | poweroutput 1 hr = {{convert|3150|kW|hp|abbr=on}} | poweroutput cont = {{convert|3000|kW|hp|abbr=on}} | tractiveeffort = | t/e starting = {{convert|450|kN|lbf|abbr=on}} | t/e 1 hr = {{convert|319|kN|lbf|abbr=on}} | t/e continuous = {{convert|300|kN|lbf|abbr=on}} | factorofadhesion = | f/adh starting = | f/adh 1 hr = | f/adh continuous = | locobrakeforce = | operator = South African Railways<br />Spoornet<br />[[Transnet Freight Rail]] | operatorclass = Class 7E1 | numinclass = 50 | fleetnumbers = E7101-E7150 | officialname = | nicknames = | axleloadclass = | locale = | deliverydate = 1980-1981 | firstrundate = 1980 | lastrundate = | withdrawndate = | preservedunits = | restoredate = | scrapdate = | currentowner = | disposition = | notes = }}
The '''South African Railways Class 7E1''' of 1980 is an electric locomotive.
In 1980 and 1981, the South African Railways placed fifty Class 7E1 electric locomotives with a Co-Co wheel arrangement in mainline service.<ref name="E&D diagram-book">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</ref>
==Manufacturers== The 25 kV AC Class 7E1 electric locomotive was designed for the South African Railways (SAR) by [[Hitachi]], while [[DCD (company)|Dorbyl]] in South Africa supplied the mechanical components. The first six locomotives, numbered E7101 to E7106, were built by Hitachi in Japan in 1979, while forty-four more were built by Dorbyl in South Africa between 1979 and 1981, numbered in the range from E7107 to E7150.<ref name="Paxton-Bourne">{{Paxton-Bourne|pages=129-131}}</ref><ref name="Middleton">{{Middleton-SA Loco Guide|pages=51, 61}}</ref>
Like Union Carriage and Wagon, neither Hitachi nor Dorbyl allocated builder’s numbers to the Class 7E1 locomotives they built for the SAR, but used the SAR unit numbers for their record keeping.<ref name="E&D diagram-book"/>
==Features==
===Appearance=== [[Image:SAR Class 7E1 E7133 ID.JPG|thumb|left|x100px|[[Builder's plate]]]] Since they were acquired solely for use on the Richards Bay coal line where they would always work in multiple unit lashups, they were built with single cabs. Following the Class 9E which had entered service in 1978, the Class 7E1 was the second single cab mainline electric locomotive to be acquired by the SAR. Until the Class 9E was introduced in 1978, all South African mainline electric locomotives were dual cab units.<ref name="E&D diagram-book"/>
The two sides of the Class 7E1 are sufficiently different in appearance that, when coupled end to end, a pair of them appears at first glance to be two different locomotive types. The left side is smooth, while the right has several large grilles.<ref name="E&D diagram-book"/>
===Pantographs=== The locomotive's pantograph placement is unusual in not being equidistant from the locomotive ends. The contact shoe centre of the no. 1 end pantograph is {{convert|5280|mm|ftin|1|abbr=off}} from the longitudinal centre of the locomotive, while that of the no. 2 end pantograph is {{convert|6250|mm|ftin|1|abbr=off}} from the centre.<ref name="E&D diagram-book"/>
===Brakes=== Control of traction and rheostatic braking on the Class 7E1 is by stepless solid-state electronics. The electrical equipment was designed for high power factor operation, obtained by the switching in of power-factor correction capacitors.<ref name="Paxton-Bourne"/>
Unlike the [[South African Class 7E|Classes 7E]] and [[South African Class 7E2, Series 1|7E2]], where thyristors are used, these locomotives use silicon-diode rectifiers.<ref>Jane's Train Recognition Guide</ref>
In the period from the early 1990s until about 2007, various modifications to improve downhill braking capacity were done to the Coalink line's Hitachi-designed locomotives. The first set of upgrades were done on the fifty Class 7E1 locomotives. They retained their Class 7E1 classification after modification.<ref name="Paxton-Bourne"/><ref name="Middleton"/>
===Bogies=== Like the [[South African Class 6E1, Series 1|Class 6E1]] and [[South African Class 7E|Class 7E]], the Class 7E1 was built with sophisticated traction linkages on the bogies. Together with the locomotive's electronic wheel-slip detection system, these traction struts, mounted between the linkages on the bogies and the locomotive body and colloquially referred to as grasshopper legs, ensure the maximum transfer of power to the rails without causing wheel-slip by reducing the adhesion of the leading bogie and increasing that of the trailing bogie by as much as 15% upon starting off.<ref name="Paxton-Bourne"/>
==Service== The Class 7E1 was placed in service on the 25 kV AC Ermelo-Richards Bay Coalink line, where most of them still work. By 2015 some had been transferred to Pyramid South.<ref name="Paxton-Bourne"/>
==Liveries== All the Class 7E1 locomotives were delivered in the SAR Gulf Red livery with signal red cowcatchers, yellow whiskers and with the number plates on the sides mounted on three-stripe yellow wings. In the late 1990s many were repainted in the Spoornet blue livery with either outline or solid numbers on the sides and with a yellow and blue chevron pattern on the cowcatchers. After 2008 in the [[Transnet Freight Rail]] (TFR) era, several received the TFR red, green and yellow livery.<ref name="Soul of a Railway 7-9">[https://sites.google.com/site/soulorailway/home/system-7-1/south-eastwards-as-far-as-volksrust-2nd-section-wattles-to-union-junction-by-les-pivnic Soul of A Railway, System 7, Western Transvaal, based in Johannesburg, Part 9. South-Eastwards as far as Volksrust (2nd part) by Les Pivnic. Caption 4.] (Accessed on 11 April 2017)</ref>
==Illustration== <gallery mode=packed heights="200px"> File:SAR Class 7E1 E7137.JPG|No. E7137 in SAR Gulf Red and yellow whiskers livery at [[Vryheid]], KwaZulu-Natal, 15 August 2007 File:Class 7E1 E7108.jpg|No. E7108 in Spoornet blue livery with solid numbers, Pyramid South, Gauteng, 22 September 2015 File:SAR Class 7E1 E7145.JPG|No. E7145 in Spoornet blue livery with outline numbers at [[Richards Bay]], KwaZulu-Natal, 14 August 2007 File:Class 7E1 E7138.jpg|No. E7138 in [[Transnet Freight Rail]] livery, Pyramid South, Gauteng, 22 September 2015 </gallery>
==References== {{Commons category|South African Class 7E1}} {{Reflist}}
{{Locomotives of South Africa}}
[[Category:Electric locomotives of South Africa|2990]] [[Category:Co-Co locomotives]] [[Category:Hitachi locomotives]] [[Category:Dorbyl locomotives]] [[Category:Cape gauge railway locomotives]] [[Category:Boxcab locomotives]] [[Category:Railway locomotives introduced in 1980]] [[Category:1980 in South Africa]] [[Category:25 kV AC locomotives]]