C-AKv coupling

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The C-AKv coupling (compact - automatic coupling simplified) is a fully automatic central buffer coupling for railway vehicles developed by Faiveley Transport , which was developed as a replacement for the European screw coupling . It has the Willison profile of the Russian SA-3 coupling and can be coupled without an adapter to both the European screw coupling and the SA-3 and the previous UIC central buffer coupling.

history

C-AKv coupling on a class 189 locomotive for use in front of ore trains

As early as the 1970s, the UIC central buffer coupling (type AK69e or Intermat) was developed as a new type of coupling for European railways. It was supposed to replace the European screw coupling, which is not very resilient, is labor-intensive and time-consuming and causes high maintenance costs. A Europe-wide introduction has been postponed again and again. Since the shape was not compatible with the screw coupling, an extensive simultaneous change would have been necessary, which some member states could not afford financially. The mixed coupling, which was developed at the same time, was only approved for shunting service at the time.

The C-AKv coupling was developed by SAB WABCO , now Faiveley Transport Witten GmbH. In contrast to the UIC central buffer coupling, the C-AKv coupling is compatible with the screw coupling without additional equipment, so that the vehicles can now be converted gradually. Since 2002 it has been in continuous testing on coal trains operated by DB Schenker Rail between the Profen open-cast mine and the Schkopau power plant . DB Schenker Rail (until 2008 under the name Railion ), Faiveley and the TU Berlin worked out possible strategies for the long-term switch to the C-AKv coupling from 2008 to 2011.

In 2009, the Siemens plant in Munich-Allach received the order from Railion to equip 18 existing locomotives of the 189 series with the C-AKv coupling. This is intended to drive ore trains with a mass of up to 6000 t on the Rotterdam – Dillingen (Saar) route . The integrated line coupling is used with two air lines, namely for the main air line , which is used for braking, and the main air tank line , which is used to supply pneumatically operated consumers in the car. The locomotives are used in double traction. In March 2010 the first four locomotives with C-AKv couplings were put into operation. The ore wagons of these trains have been in use with AK69e couplings for years; they are being converted to C-AKv as part of their maintenance.

construction

Drawing of the coupling head in front view

As a heavily modified further development of the UIC central buffer couplings , the C-AKv coupling is based on the shape of the SA-3 coupling . Compared to the SA-3, compressed air lines and (optional) electrical connections are integrated in the coupling, so that no manual work is required for coupling. In contrast to previous designs, which were supposed to replace the ineffective screw coupling in Europe and failed (albeit not for technical reasons), the C-AKv coupling is compatible with this. One of the main reasons for the failure was the immense cost of retrofitting across Europe or across the country. In the meantime, however, the mixed coupling has proven its suitability for safe train operation both in Finland and for the operation of the transfer and coupling wagons , so a simultaneous changeover would no longer be necessary.

Mixed coupling is made possible without an adapter with the screw coupling because the air and electrical connections, which were arranged under the mechanical coupling in the rigidity organs of the UIC central buffer couplings, are built into the Willison profile itself, namely on the outer surface of the small tooth and the corresponding contact area. This leaves space underneath for storing the coupling chain, based on the model of the 'Unilink' dome head. Thus the design is much more compact than the previous designs; The shape differs from the SA-3 coupling, apart from the connections themselves, visually only through the rigidizing organs in the form of a horn on the front of the large tooth and a corresponding pocket on the small tooth, which are placed on the sides of the Willison profile and which interlock on both sides when coupling.

For coupling with SA3 and UIC central buffer couplings, the air and electrical connections must be folded out of the Willison profile by hand and the lines connected manually.

Advantages and disadvantages

Resilience

The C-AKv coupling has an approved tensile load of 1000 kN and a shear load of 2000 kN (screw coupling: 500 kN / 1000 kN). For lane change traffic to Russia, there is a variant with 2500 kN tractive force and 3000 kN compressive force. Due to this higher load capacity under tensile and compressive loads as well as the central introduction of forces into the vehicle, significantly heavier trains can be transported. When driving uphill, longer trains can therefore be driven with the normal locomotives or the additional pushing locomotives that are currently customary can be dispensed with. When driving downhill, the permissible speeds could be increased and the possible regenerative power of modern electric locomotives could be better utilized. This results in economic advantages through better utilization of route capacities, shorter transport times and reduced energy requirements and material wear. In rare cases, accidents could also be avoided by overbuffering. The C-AKv coupling shares these advantages over the screw coupling with the other central buffer couplings such as the SA-3, UIC and Janney coupling .

Time and personnel expenditure during the coupling process

For coupling, the railway vehicles involved only have to roll on each other until the coupling engages. All connections are automatically connected. In contrast, the SA-3 and the non-rigid versions of the Janney coupling require the intervention of an employee who connects brake lines and, if necessary, other connections in a few seconds. With the currently usual screw coupling, the coupling employee also has to do the mechanical coupling manually by hooking the chain into the draw hook and tightening the double spindle, which takes about a minute. What makes it more difficult is that the screw coupling can only be reached if you step under the buffers in a very stooped position.

The instant uncoupling of the C-AKv is done remotely from the driver's cab in the case of locomotives and control cars, in all other vehicles by pulling a lever on the side of the coupling, whereby it is sufficient to unlock one of the two connected coupling heads. This function is comparable with SA-3, UIC and Janney couplings. The chain of the screw coupling, on the other hand, has to be twisted long and loosened.

The train busbar must still be coupled and disconnected by hand. However, this does not require entering the space between the vehicles. The transition bridges of passenger coaches are to be folded down from above; this is also not necessary with pressure-tight coach transitions . The overall height and the rigid principle enable a level wagon transition without the step common in the Eastern European broad-gauge network. However, there are currently no concrete plans for converting passenger coaches.

The C-AKv shares the fast and automatic coupling process with the Scharfenberg coupling , which, however, is not suitable for freight trains due to its low load capacity. There is currently no way of coupling vehicles with Scharfenberg couplings.

safety

Since nobody has to step between the moving railway vehicles during coupling and uncoupling, there is no major source of danger for accidents, as well as the risk of injury and physical exertion when hanging and unhooking the approximately 36 kg chain of the screw coupling.

Because the longitudinal forces are introduced centrally, the trains have less of a tendency to derail when pushing than with a combination of screw couplings and side buffers. This increases safety and eliminates the need for speed restrictions in curves and the tight limitations of the pushed towing mass as well as the braking force limitation of the dynamic brake.

All rigid central buffer couplings more or less share these advantages.

Maintenance costs and wear and tear

The side buffers of railway vehicles that are connected with screw couplings must be greased and replaced regularly. While all vehicles with C-AKv couplings have side buffers for the transition period to allow a mixed coupling, these do not incur any maintenance costs as long as the coupling is carried out according to type. The wear of permanently connected central buffer couplings is lower by orders of magnitude.

The reduced wear of the wheel sets is even more important financially: Since central buffer couplings with suitable bearings can pass on transverse forces, there are lower lateral forces between the wheel flange and the rail. Wheel tires and rails wear out much more slowly. In a field trial from the Profen opencast mine to the Schkopau power plant, the C-AKv coupling was tested from 2004, in which the number of wheel sets changed was reduced to less than a third during the observation period.

acquisition cost

Compared with the technically primitive screw coupling that is widespread across Europe, the acquisition costs of the C-AKv coupling are higher. For the coal trains mentioned above, those responsible estimate the amortization time at around 5 to 10 years, due to the high savings in the wheelsets. The potential savings are very different depending on the goods being transported, the type of transport ( single wagon / block train transport, combined transport ) and the degree of mixing with the conventional screw coupling.

Railway vehicles that are prepared for conversion to the European UIC central buffer coupling do not require any further conversion to accommodate the C-AKv coupling.

UIC conformity

In contrast to the unchanged SA-3 coupling and the Janney coupling, the C-AKv coupling meets the requirements of the UIC , which led to the development of the UIC central buffer coupling; it complies with the UIC 522-1 standard. Among other things, this includes reliable coupling in the tight curve radii of Western and Central Europe.

In particular, the coupling is compatible with installation frames according to UIC 530-1, which have been installed on numerous railway vehicles since the 1980s.

TSI conformity

The Technical Specification for Interoperability (TSI) from 2006 (2006/861 / EC) applies within the European Union. This stipulates that wagons must be able to be coupled with the screw coupling system. This can also be made possible via an auxiliary coupling. The C-Akv coupling meets the requirements in combination with side buffers. A revision of this TSI is necessary if the C-Akv is to become the standard coupling.

Longitudinal jerk

Without additional buffers, there is play in the longitudinal direction between adjacent carriages, which leads to longitudinal jolts. This is not desirable in passenger traffic for reasons of comfort. Technical additions such as fixed rubber buffers directly on the coupling are therefore discussed. It shares this characteristic with the SA-3 coupling. Side buffers are located on passenger coaches equipped with SA-3 in order to apply permanent tension to the coupling .

literature

  • Franz Peter Bartling, Jörg Bensch, Manfred Driesel, Dr. Isolde Gasanov: Use of the TRANSPACT central buffer coupling (C-AKv) in coal transport . In: Eisenbahntechnische Rundschau , vol. 55 (2006), issue 9, ISSN  0013-2845
  • Jürgen Janicki, Horst Rheinard: Rail vehicle technology . Bahn Fachverlag, Heidelberg 2008. ISBN 978-3-9808002-5-9 .

Web links

Individual evidence

  1. ^ Jens Chlebowski: Mobility Lokomotivenwerk Munich. (PDF; 1.1 MB) Siemens, March 31, 2009, p. 11 , accessed on August 30, 2014 .
  2. ↑ MIH - MRF: Locomotive train with 4 x BR 189 to the north (m4B). In: turntable online forums. March 9, 2010, accessed August 30, 2014 .
  3. ↑ Type description of DB freight wagons. (No longer available online.) In: Virtuelle Bahnwelt. Formerly in the original ; accessed on August 30, 2014 .  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Toter Link / www.virtuelle-bahnwelt.de  
  4. ↑ Holger Gayer: What does overbuffering mean? In: website. Stuttgarter Zeitung , October 9, 2012, accessed on January 17, 2018 .
  5. ↑ Werner Deinert: Railway carriages. 5th edition. Transpress VEB Verlag for Transport, Berlin 1985, p. 92.
  6. ↑ Helge Johanes Stuhr: Investigation of application scenarios of an automatic central buffer coupling (dissertation) . Technical University Berlin. P. 46.47. February 26, 2013. Retrieved March 11, 2015.
  7. ↑ Technical specification for the interoperability of the European Union (PDF; 6.0 MB) - the specifications for the coupling system start from page 33
  8. ↑ BT-Drucksache 17/4478 (PDF; 82 kB) - Statements of the federal government on the C-Akv coupling