SNCF BB 13000
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TheBB 13000class wereelectric locomotivesoperated bySNCFin France. They were one of four classes, together with theBB 12000,CC 14000andCC 14100classes, that formed an experimental group for studying the practicality of the new French25 kV 50 Hz ACelectrification.[1]
25 kV 50 Hz electrification
[edit]The standard French electrification system before WWII was 1,500 V DC, beginning with locomotives such as the2BB2 400.Post-WWII, Franceoccupiedthe south-west of Germany and theHöllentalbahn.[2]This line had been electrified with one of the first systems to use 50 Hz, the standard commercial distribution frequency, rather than the lower16+2⁄3Hz AC frequency previously required for railwaytraction motorsin Europe. The Höllentalbahn used a voltage of 20 kV.
There was much interest post-war in using the 'industrial' frequency of 50 Hz and supplying the railways from the now established national systems of electricity generation, rather than requiring an isolated supply network for railways alone. The first French 50 Hz AC line, theAix-les-Bains to Annemasse line,was in theHaute-Savoie,using a small quantity of experimental motive power. It began at 20 kV in 1951, as for the Höllentalbahn, but in 1953 the voltage was raised to 25 kV.[3]As this was successful, a second 25 kV electrification of 'la Transversale Nord-Est', the 300 kilometres (190 mi)Valenciennes-Thionville linebetweenThionvilleandValenciennes,was tried.[4][5]This carried three express trains and a hundred freight trains each day, with gradients of up to 1:90.[6]It was significantly a mineral line, bringing coal from the mines of the North to the ironworks of the Lorraine.[5]
To investigate the best system for taking the industrial frequency line current and delivering it to the traction motors, four similar classes of locomotive were constructed, each using a separate technique. One class, the BB 12000, was to be geared fast enough for express passenger services at 120 km/h (75 mph), the others for mixed-traffic or freight.[6]In 1952 orders for 85 locomotives were placed: five BB 12000, fifteen BB 13000, twenty CC 14000, sixty five CC 14100.[5]
Design
[edit]The four classes each took a different approach to the use of the AC supply current.[1]The first, theBB 12000,used DC traction motors withignitronrectifiers;the BB 13000 used new 50 Hz AC traction motors; theCC 14000used DC traction motors with rectification byrotary convertersand theCC 14100used three-phase AC traction motors, again with rotary converters. The first two classes were ofB′B′layout with two four wheel bogies and a separate traction motor for each axle. As the axles were mechanically coupled by gearing though, they were classified as B′B′ rather than Bo′Bo′. Owing to the greater weight of the rotary converters, the 14000 and 14100 had aCo′Co′layout with extra axles to carry their weight without increasing theaxle load.
The BB 13000 system was designed byJeumont-Schneider.The 25 kV line current was regulated by anautotransformerthen transformed by the main transformer to 750 V AC. This secondary current drives the four single-phase traction motors (one per axle) connected in parallel. Motor speed was controlled by resistor and capacitor shunts at low speeds, resistor and inductor shunts at high speeds.[7]
This AC motor system did not have the advantages of the traction control of the BB 12000 series and their DC motors with precise control from theignitronphase control.[6]It was found that although the AC motor system was initially simpler to build as it did not need rectifiers, it was not so well-suited to low speed and accelerating from frequent stops, and so it was generally restricted to longer non-stop mainline services.[8]Oncesilicon rectifiersbecame available to replace the ignitrons, as had been used on the last of the BB 12000, this became the dominant way to build all AC electric locomotives for decades.
The 'Jacquemin' bogie designs were taken from theSNCF BB 9003,but shortened and simplified as the locomotives were of lower speed. This bogie used two separate traction motors withcardan shaftconnection to the wheels, rather than the previous French 'dancing ring' design. As these bogies mechanically coupled the two motors, they are classed as aB′B′arrangement, rather thanBo′Bo′.
The body style was asteeplecabwith a single 'monocabine' central control cab and long, low bonnets at each end. The single cab design was chosen because previous experience had suggested that providing duplicated control gear at the ends of the locomotive was the least reliable part of an electric locomotive, and this way only one set might be needed, with direct access to it. However this simplicity also prevented the locomotives being connected inmultiple.[9]The driver was also better protected in case of accident. The twodiamond pantographsrequired more space than the cab roof and so were supported on two distinctive cantilevered platforms, ahead and behind the cab.[6]The steeplecab and its overhanging pantograph platforms gave them the nickname of 'flatirons'. Some drivers also knew them as 'trancheur de jambon' from the control wheel's resemblance to that of abacon slicer.
Service history
[edit]
Both the BB 12000 and BB 13000 classes had cramped cabins and relatively poor braking. The BB 12000 were clearly electrically superior though. The BB 13000 class began to be withdrawn in the 1980s and the last operated in January 1994.[8]
Preservation
[edit]Two are preserved as static exhibits
- BB 13044:Centre de la Mine et du Chemin de FeratOignies
- BB 13052:Cité du trainatMulhouse
References
[edit]- ^abCuynet, Jean (2008)."Les débuts du courant" industriel "à la SNCF"[The beginnings of 'industrial' current on the SNCF](PDF).J3eA, Journal sur l'Enseignement des Sciences et Technologies de l'Information et des Systèmes(in French).7.EDP: 1–13.doi:10.1051/j3ea:2008040.Retrieved1 September2017.
- ^Leuzzi, Vincenzo(1955). "The Höllenthal Railway and the Monophase 50 Hz System".Railway Engineering Abstracts.Institution of Civil Engineers.
- ^"Tableau chronologique de l'électrification du réseau SNCF".Revue de l'AFAC.1988–6 (393).AFAC:261–266.
- ^Picard, Jean-François (1997)."Histoire de l'électrification des chemins de fer français"[History of electrification of French railways].
- ^abcCuynet (2008),p. 5.
- ^abcdHollingsworth, Brian; Cook, Arthur (2000). "Class 12000 Bo-Bo".Modern Locomotives.pp. 112–113.ISBN0-86288-351-2.
- ^Cuynet (2008),p. 9.
- ^abCuynet (2008),p. 10.
- ^Cuynet (2008),p. 6.
Further reading
[edit]
- Dumont, Pascal (1994).Les locomotives électriques monophasées de l'artère Nord-Est[The single-phase electric locomotives of the northeastern artery]. Éditions du Cabri.
- Defrance, Jacques (1969).Le matériel moteur de la SNCF[The motor equipment of the SNCF] (reissue 1978 ed.). Paris: éditions NM.
- Constant, Olivier (2008).Les locomotives et automotrices 25 000 V monophasé[The 25,000 V single-phase locomotives and railcars]. Encyclopedia of motor equipment SNCF. Vol. 5, Hors série.