Cant

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A steep curve of a cycling track

Elevation is a transverse slope of a roadway in a curve towards the inside of the curve. The purpose of the elevation is to let the force resulting from the centrifugal force and weight of the vehicle act as perpendicularly as possible to the road surface in order to prevent the vehicle from skidding or tipping over. Superelevations are used:

Railways

Elevated track
Curve elevation at the Geisberg tunnel

In the case of railways, the cant is specified by the difference in height between the two rails on a track . The superelevation means that radii can be traveled at higher speeds without the cargo or passengers being subjected to strong acceleration to the side or a rail vehicle derailing. It also reduces the uneven wear of the rails. A compensating cant is the cant which eliminates the transverse acceleration acting on the rail vehicle when a design speed is reached.

The requirement that a safe emergency stop of a rail vehicle must be possible at every point on the route results in a maximum cant in order to prevent the vehicle from tipping inwards when the vehicle is stationary. In Germany, for limited regelspurige applicable Railways Railway Construction and Operating Regulations , the elevation to a maximum of 180 mm. This corresponds to a cross slope of 12.5% ​​or 7.1 degrees. Due to tolerances in the construction and maintenance of tracks, the maximum permissible cant for German infrastructure operators is 160 mm for ballast superstructures and 170 mm for slab tracks . In the area of ​​platforms, significantly less elevation is usually permitted. Here the control limit value (value that should not normally be exceeded) is 60 mm. The absolute limit for the cant on platforms is 100 mm, but this is the discretionary limit (value that may only be used if there is a compelling reason).

In the case of multi-track level crossings in elevated track curves, all rails should be on one level.

The TSI provides for a cant of up to 160 mm (on ballasted track) or 170 mm (on slab track ) for mixed traffic routes, which are used by passenger and freight traffic , on pure passenger traffic routes up to 180 mm (with both types of track). In the SNCF Réseau network , a cant of 160 mm is permitted on mixed traffic routes, in exceptional cases up to 180 mm.

Cant deficit

The cant deficiency is the difference between the cant, which would be necessary to fully compensate for the lateral acceleration at the maximum permissible speed, and the actual cant of a track curve. The specification of the maximum cant deficit in the regulations thus limits the lateral forces to which passengers and cargo can be exposed.

Standard-gauge locomotives and passenger cars that comply with the TSI must allow 153 mm cant deficiency up to 300 km / h, and 100 mm above this. 130 mm is required for freight wagons. Trains specially designed for operation with higher cant deficits may be operated with higher cant deficits, provided that operational safety is proven. For broad gauge railways Special regulations apply.

According to the German Railway Building and Operating Regulations , the cant deficit is to be determined “depending on the nature of the superstructure, the type of vehicle and the load and its securing; it should not be larger than 150 mm. ”( § 40 (7) EBO ) According to the rules of DB Netz AG, this value is generally 130 mm. In the case of rail vehicles with the corresponding approval, curves of at least 650 m radius up to 150 mm can be used. For arcs between 250 m and 650 m, a cant deficit of more than 130 mm (up to 150 mm) can be planned with the approval of the DB network headquarters. In the speed range up to 160 km, speeds up to 10 km / h higher can be permitted, in individual cases up to 20 km / h. A lower single-digit percentage range of the route network actually uses the leeway of 130 or up to 150 mm. Passenger trains licensed in Germany from 1999 onwards have to be designed for a 150 mm cant deficit; a large number of mainline vehicles are licensed for this. The standard DIN EN 14363, which came into force in 2005, also requires a permissible cant deficiency of 150 mm for “conventional passenger vehicles”. Exceptions are permitted and may be. a. used for two-system vehicles that are also approved according to BOStrab . Speeds that result from cant deficits over 130 mm are usually recorded in the Deutsche Bahn network in a separate column in the directory of permissible speeds (VzG) and taken into account accordingly in the electronic book timetable for suitable trains.

In the area of points and rail extensions, limit values ​​between 90 and 130 mm apply to the infrastructure of DB Netz:

  • For inner curved turnouts with a rigid frog up to 200 km / h up to 110 mm, over 200 to 230 km / h, coordination with the DB network center is necessary.
  • For outer curved turnouts with a rigid frog, 100 mm is permissible up to 160 km / h, 90 mm above 160 and 200 km / h, and above that, up to 230 km / h, coordination with the DB network center is required.
  • In the case of points with a movable frog point , up to 200 km / h up to 130 mm are permitted, up to 250 km / h up to 100 mm, beyond this to be clarified with the DB network center in individual cases.
  • in curved crossings and curved crossings, 100 mm are permitted up to 160 km / h.
  • up to 200 km / h 100 mm are permissible in rail extensions in a curve; coordination with the DB network center is required for higher speeds.

With the approval of the DB network headquarters, the values ​​for switches, crossings, crossings and rail extensions can be exceeded by up to 20 percent.

In operation at high speed , cant deficits without constrained points of up to 300 mm are permitted. In the case of constrained points (e.g. curved switches, bridges without ballast bedding and level crossings with rigid surfaces) 150 mm is permitted, in rail extensions 130 mm.

According to the TSI, cant deficiencies of up to 180 mm are permitted, and up to 190 mm on pure passenger traffic routes. Up to 180 mm are permitted in the SNCF network, with deviations in operation of up to 15 mm. As a rule, 110 mm are permitted for freight trains, in exceptional cases up to 130 mm.

Since 2017, driving with 180 mm cant deficiency has been allowed in Sweden (train category C). This is used by the MTR X74 , among others .

In Switzerland and Spain, the permissible cant deficits are defined in so-called train series n.

In the European Train Control System (ETCS), there are 18 different train categories. a. A distinction can be made according to the type of pull, tilting technique, braking position and permissible cant deficits. The permissible cant deficiencies are between 80 and 150 mm without tilting technology and between 165 and 300 mm with tilting technology. When determining the permissible speed on ETCS Level 2 routes in Germany, which are used in mixed traffic by passenger and freight trains, a cant deficit of a maximum of 130 mm may be taken into account. As part of the introduction of Baseline 3 , different speed profiles should be available in Germany in the future. Until then, compared to conventional signaling, this can lead to selectively reduced permissible speeds for trains guided by displays .

realization

A height offset within the rail cannot be driven over, so that the elevation is created by so-called elevation ramps . The rails are rigidly connected to the sleepers . In order to achieve the different heights of the rails, they are installed in an inclined position in the ballast bed . The simplest form of production is the implementation of a linearly increasing cant, which usually coincides with a transition curve (clothoid) in the floor plan . In addition, there are cant ramps in practice, which are based on the layout of transition arches 4th order (s-shaped) or 5th order (Bloss). The French state railway realizes the necessary cant ramps with the so-called doucine , which is a straight cant ramp with rounded edges at the beginning and end. Taking into account the rounding reduces the jerk that occurs at the transitions with conventional straight superelevation ramps. This enables a shorter development length and thus steeper longitudinal slopes .

history

At the end of the 19th century, there was a fixed relationship between radius and permissible speed in Germany. The highest permissible speed of 90 km / h was permitted with a 1000 m radius of curvature. Elevations of more than 100 mm should be avoided in order to prevent the inner rail from inclining too much to the outside. In the area of ​​the Association of German Railway Administrations there were nevertheless up to 250 mm cant, although the handling was not uniform and arbitrary even within the same railway administration. In Belgium there was a fixed relationship between radius and permissible speed ( ), as was the case in Austria-Hungary ( ) (V in km / h and R in meters). In France up to 200 mm cant was laid. According to other information from Germany, on the threshold of the 20th century, 120 mm was considered the greatest possible cant.

In order to avoid arbitrariness, the technical committee of the Association of German Railway Engineers developed a formula that had proven itself on the Prussian state railways on the left bank of the Rhine and Hanoverian lines and took scientific considerations into account: (with travel speed V in km / h, radius of curvature R in m and the constant m). In Prussia , the maximum permissible cant was 135 mm in Prussia.

British studies with a 2-car multiple unit came to the conclusion in 1949 that accelerations and decelerations of more than about 1.1 m / s² were perceived as unpleasant. Standing passengers reacted a little more sensitively than seated passengers.

In the early 1950s, the German Federal Railroad (DB) allowed 150 mm and 100 mm cant deficit without restriction. At the beginning of the 1960s, the superstructure of the 150 mm elevated tracks was considered maintenance-intensive in the DB area, especially on heavily used freight train routes. On the other hand, for low-speed railway lines, such as S-Bahn trains, an increase to 180 to 200 mm was considered conceivable. According to new tests, an increase in the cant deficit to 130 mm "taking into account the dining car operation " was considered harmless.

With the new version of the Railway Building and Operating Regulations of May 28, 1967, a limitation of the permissible cant to 150 mm was added. Larger excesses require approval by the Federal Minister of Transport. The cant deficiency was simultaneously increased from 100 to 130 mm (corresponding to a residual lateral acceleration of 0.85 instead of the previous 0.65 m / s²). The permissible speed in the curve was calculated according to (with speed V in km / h, curve radius R in meters and superelevation u in millimeters). The changes were preceded by test drives, which did not lead to any noticeable reduction in travel comfort.

When, with the timetable change in 1968/1969, the majority of the arches on the main discharge routes were driven on at increased speeds, disturbances in smoothness and comfort were found in many places. Investigations in the following years led from 1971 to the adjustment of the routing regulations. After more than 80 percent of the faults in the vehicle movement occurred at switches, level crossings and ballastless bridges, the permissible cant deficiency was reduced to the previous limit of 100 mm. The application of the EBO limit value of 130 mm was limited to unconstrained curved tracks on good ground.

From the end of the 1970s, the principles of line routing were incorporated into the new “Regulation for the design of railway systems - DS 877 -” at the Deutsche Bundesbahn, the name of which was later changed to DS 800 in order to emphasize its fundamental character. The lines and other design principles were the subject of subsection DS 800/1 (“General Design Fundamentals”). At the beginning of the 1980s, a preliminary specification was available for the part 800/2 (for new lines), the other eight parts were in preparation.

Around 1988 the Deutsche Bundesbahn expected the maximum cant to be increased to 160 mm and the cant shortfall to 150 mm as part of a foreseeable amendment to the EBO. The use of these so-called superstructure forecast values ​​was permitted around 1989 if, compared to the application of the EBO limit values ​​(150 mm cant / 130 mm cant deficit), jump costs could be avoided and heavy superstructure (UIC 60 rails and B 70 W concrete sleepers) were used. Test drives and approval from the headquarters of the Deutsche Bundesbahn were required.

With the Third EBO Amendment Ordinance in 1991, the operational limit for the cant was finally raised from 150 to 180 mm. While the previously applicable upper limit of 150 mm was also produced in practice, the new limit of 180 mm also expressly included deviations that arose in operation beyond the production dimensions. In the case of particularly well-maintained tracks - taking into account the monitoring and maintenance strategy - canting of up to 160 mm on ballast superstructure and 170 mm on slab track could be permitted. The cant deficit of up to 130 mm, which had been in effect until then, was increased to up to 150 mm. At the same time, it was made clear that the cant shortfall - like the cant - depends on various criteria and safety-relevant changes to the target dimensions for cant and radius are possible during operation. The Federal Ministry of Transport has been authorized, as an exception - for tilting trains, for example - to allow cant deficits of more than 150 mm. The values ​​of 160 mm superelevation and 150 mm superelevation deficit had previously been verified in an interdisciplinary study by the Federal Railway Central Office in Munich.

A dissertation presented in 1991 showed that when the slab track was used, due to greater track stability and lower dynamic forces, the cant deficiency could be increased to 180 to 200 mm under suitable boundary conditions.

Motorsport

NASCAR starter field drives into the banked curve.

In the early days of motorsport, canting was to be found in the form of banked curves on many racetracks, examples still known today are Monza , the AVUS or the concrete bend of the old Nürburgring . Because of the safety discussions in the 1960s / 1970s, many steep turns were cut back in Europe. Today there are only a few superelevations, one of the most famous corners is the Caracciola carousel on the Nordschleife of the Nürburgring. Almost all of the oval courses customary in the USA have a camber, the Talladega Superspeedway has the steepest curves at 33 °.

Web links

Individual evidence

  1. ↑ See Railway Building and Operating Regulations (EBO) § 1 (scope).
  2. ^ Railway building and operating regulations (EBO). Accessed on June 5, 2013 (§ 6 Paragraph 3): “The cant is to be determined depending on the nature of the superstructure, the type of vehicle and the load and its securing; taking into account the deviations that occur during operation, it must not exceed 180 mm. "
  3. ↑ a b c d e f g h i j Robert Rausch: Guideline 800.0110 . Lines. Ed .: DB Netz. November 20, 2019, p. 10–12, 27 (valid from December 1, 2015).
  4. ↑ a b Opinion of the European Union Agency for Railways for the European Commission regarding FR request for new specific cases in INF and ENE TSIs. (PDF) European Railway Agency, December 17, 2019, p. 8 f. , accessed on March 14, 2020 (English).
  5. ↑ Regulation (EU) No. 1299/2014 , Section 4.2.4.3.
  6. ↑ a b Alexander Staffel: Expansion of the use of the cant deficit of 150 mm . In: The Railway Engineer . tape 71 , no. 6 , June 2020, ISSN  0013-2810 , p. 55-58 .
  7. ↑ Johan Kristensson: Tågutmanare får ta kurvorna snabbare. Retrieved May 8, 2020 (Swedish).
  8. ↑ ERTMS OPERATIONAL PRINCIPLES AND RULES. (PDF) European Union Agency for Railways , April 9, 2019, p. 67 , accessed on November 29, 2019 (English, “version 5”).
  9. ↑ Markus Suiter: Principles for creating the implementation planning PT1 for ETCS Level 2 . Directive 819.1344. Ed .: Deutsche Bahn. September 4, 2019, p. 51 .
  10. ↑ a b Barkhausen , Blum, from Borries: The railway construction of the present . CW Kreidel's Verlag, Wiesbaden 1897, p. 118-121 .
  11. ↑ a b Gerhard Schramm : Railway track and express transport . In: The Federal Railroad . 1963, ISSN  0007-5876 , p. 42-52 .
  12. ↑ a b Erich Giese , Otto Blum , Kurt Risch: Linienführung (=  Robert Otzen [Hrsg.]: Reference library for civil engineers . Volume 2 , no. 2 ). Julius Springer , Berlin 1925, p. 211 f .
  13. ^ Viktor Kammerer: Magazines and short news . In: Electric Railways . tape 24 , no. 7 , 1953, ISSN  0013-5437 , pp. 182 .
  14. ^ Heinz Delvendahl: The railway systems in the new railway building and operating regulations (EBO) . In: The Federal Railroad . tape 41 , no. 13/14 , 1967, ISSN  0007-5876 , pp. 453-460 .
  15. ↑ a b Manfred Weigand: Update of the routing elements for routes with design speeds of up to 200 km / h . In: Railway engineer calendar . 1988, ISSN  0934-5930 , ZDB -ID 623051-9 , p. 113-129 .
  16. ^ Klaus Jacobs, Peter Hermann: The DS 800 - regulation for the design of railway systems - a basis for the work of the structural planning engineer . In: The Federal Railroad . No. September 9 , 1982, ISSN  0007-5876 , pp. 657-659 .
  17. ^ Lothar Semisch, Hans Dieter Stüwe: publications of the German Federal Railroad . In: Elsner's paperback of railway technology . 1982, ZDB -ID 242938-X , p. 497-533 .
  18. ↑ Horst Ritthaler: ABS Günzburg – Augsburg . In: Die Bundesbahn , 64, No. 10, 1988, ISSN  0007-5876 , pp. 1017-1020.
  19. ^ Carsten Lorenzen: The upgraded Würzburg – Nuremberg line . In: The Federal Railroad . tape 65 , no. 10 , 1989, ISSN  0007-5876 , ZDB -ID 1372-9 , p. 831-836 .
  20. ^ Walter Mittmann, Fritz Pätzold, Dieter Reuter, Hermann Richter, Klaus-Dieter Wittenberg: The Third Ordinance to Change the Railway Construction and Operating Regulations (EBO) . In: The Federal Railroad . No. 7-8 , 1991, ISSN  0007-5876 , pp. 759-770 .
  21. ↑ Reinhard Pospischil: Effects of a changed superstructure on the routing of the new and upgraded lines of the Deutsche Bundesbahn . Dissertation, Technical University of Munich, 1991 ( reports from the testing office for the construction of land transport routes of the Technical University of Munich , ISSN  0341-5538 , issue 62), pp. 179–182.