[[File:Class 32 GE U18C1 32-029 and 32-042 22nd September 2007 (7862994434).jpg|thumb|upright=1.3|[[South African Class 32-000]] diesel-electric]] Under the British and Imperial classification scheme of locomotive axle arrangements '''1Co+Co1''' is a classification code for a locomotive wheel arrangement of two eight-wheeled [[bogie]]s with an articulated inter-bogie connection, each with three axles powered by a separate traction motor per axle and with the fourth non-powered axle in an integral leading pony truck to reduce the axle load. The similar '''{{nowrap|[[1Co-Co1]]}}''' classification is in the same axle configuration, but without the inter-bogie connection.<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>{{page needed|date=August 2019}}
Other equivalent classifications are: * [[AAR wheel arrangement#1-C+C-1|AAR classification]]: '''[[AAR wheel arrangement#1-C.2BC-1|1-C+C-1]]''' * [[UIC classification of locomotive axle arrangements|UIC classification]]: '''(1′Co)+(Co1′)'''
==Overview== The 1Co+Co1 wheel arrangement for electric and diesel-electric locomotives was a development of the [[Co+Co]] wheel arrangement to enable a relatively heavy locomotive to work on light rail by reducing the [[axle load]]. This was accomplished by the addition of a non-powered axle in an integral pony truck to the three [[traction motor]]ed Co powered bogie.<ref name="ALCO">{{cite book | title=The American Locomotive Company - A Centennial Remembrance | first=Richard| last=Steinbrenner }}</ref>{{page needed|date=August 2019}}<ref name=lee212>{{cite book |last=Lee| first=Robert |title=The Railways of Victoria 1854-2004 |publisher=Melbourne University Publishing Ltd |year=2007 |isbn= 978-0-522-85134-2 |page=212 }}</ref>
In the [[United States of America]], the [[South African Class 32-000]] is credited with being a major factor in the demise of the [[American Locomotive Company]] (ALCO) and the rise of [[General Electric]] (GE) in the locomotive building business. In 1957, the South African Railways (SAR) called for tenders with two options.<ref name="ALCO"/>{{page needed|date=August 2019}} * 115 {{convert|1800|hp|kW|abbr=off}} locomotives with a 1Co+Co1 wheel arrangement.<ref name="ALCO" />{{page needed|date=August 2019}} * 230 {{convert|1000|hp|kW|abbr=off}} locomotives with a Co+Co wheel arrangement.<ref name="ALCO" />{{page needed|date=August 2019}}
[[File:SAR Class 32-000 32-047.JPG|thumb|[[General Steel Castings]]' bogie]] The SAR was not very enthusiastic about the [[General Motors Electro-Motive Division]] (EMD) [[two-stroke diesel engine|two-cycle engine]]s and had a strong preference for ALCO's Model 251 engine and GE's transmission systems. As a prior supplier of steam locomotives for the SAR, ALCO appeared to be virtually assured of receiving the order. [[General Steel Castings]] had a design on paper for a 1Co bogie which could be utilised by either ALCO or GE and which would enable the SAR's specification to be met for the heavier {{convert|1800|hp|kW|abbr=off}} units. The SAR made it clear that, despite the two options afforded by the tender, its strong preference was for a 1Co+Co1 locomotive. However, the use of a bogie with an integral pony truck was not universally accepted by ALCO's engineering management. The result was that ALCO bid on only the Co+Co option and lost out to GE, who had bid on both options. In South Africa, this virtually opened the floodgates for GE, since more than half of the SAR's vast [[diesel-electric locomotive]] fleet which would be acquired between 1959 and 1981 were GE products.<ref name="ALCO"/>{{page needed|date=August 2019}}
==Usage==
===South Africa=== [[File:SAR Class 4E E238.jpg|thumb|left|[[South African Class 4E|Class 4E]] electric]] The 3 kV DC [[South African Class 4E|Class 4E]] electric locomotive was designed for the SAR by the [[General Electric Company]] (GEC) and was built by the [[North British Locomotive Company]] (NBL) between 1952 and 1953. The Class 4E was amongst the most powerful narrow gauge electric locomotives in the world at that time and at {{convert|157488|kg|lt|0|abbr=off}}, it was a heavy locomotive for {{Track gauge|Cape|allk=on}}. The reasons for the leading pony truck were both to improve stability at speed and to reduce the axle load.<ref name="E&D diagram-book"/>{{page needed|date=August 2019}}<ref name="Paxton-Bourne">{{Paxton-Bourne|pages=126-127, 138-139}}</ref>
[[File:SAR_Class_32-200_32-202.jpg|thumb|[[South African Class 32-200|Class 32-200]] diesel-electric]] Between 1959 and 1961, the SAR placed 115 high-nosed [[South African Class 32-000|Class 32-000]] GE type U18C1 diesel-electric locomotives in service in [[South West Africa]], where very light rail conditions necessitated lighter axle loadings which could not be achieved with conventional three-axle bogies under a heavy {{convert|96520|kg|lt|0|abbr=off}} locomotive.<ref name="E&D diagram-book"/>{{page needed|date=August 2019}}<ref name="ALCO"/>{{page needed|date=August 2019}}<ref name="Paxton-Bourne"/>
In June and July 1966, ten low-nosed [[South African Class 32-200|Class 32-200]] GE type U20C1 diesel-electric locomotives entered service on the SAR. The Class 32-200 was actually a [[South African Class 33-000|Class 33-000]] locomotive on the 1Co bogies of the Class 32-000, which reduced its axle load from the {{convert|15749|kg|lt|1|abbr=off}} of the Class 33-000 to {{convert|12700|kg|lt|1||abbr=off}}. Apart from the bogies, which necessitated a smaller fuel tank, its physical dimensions and exterior appearance were identical to that of the Co+Co Class 33-000 and it used the same V12 prime mover.<ref name="E&D diagram-book"/>{{page needed|date=August 2019}}<ref name="Paxton-Bourne"/>
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=== Japan === [[File:EF1018 Shibaura Factory 193803.jpg|thumb|Japanese [[JNR Class EF10|EF10]] in 1938]] A number of Japanese electrics from the 1930s, also on Cape gauge, such as the [[JNR Class EF10|EF10]] also used this arrangement.
{{clear left}} ==References== {{Reflist}}
[[Category:1-C+C-1 locomotives| ]] [[Category:(1′Co)+(Co1′) locomotives| ]] [[Category:1Co+Co1 locomotives| ]] [[Category:Commonwealth classification]]