Pressure-capable rail vehicles

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Under druckertüchtigten rail vehicles are understood locomotives and passenger coaches that against sudden pressure fluctuations are protected. Aspects of printing comfort for travelers also play a role here. This must be distinguished from compressive strength , which relates to the mechanical resistance of a rail vehicle to compressive forces .

Pressure-tight bellows-wagon transition on ICE 1

In railway traffic , rapid pressure changes occur in the interior of the vehicle, particularly when traveling through tunnels at higher speeds, which can lead to unpleasant feelings of pressure and blocked ear trumpets , hearing damage and even fainting .

With the advent of high- speed lines and high-speed trains from the 1960s in Japan , from the 1970s at the SNCF in France and from the 1980s at the DB in Germany, this problem became more and more important.

The pressure waves that occur when driving through tunnels at speeds of up to 250 km / h can lead to discomfort or ear pain, especially when trains meet, if they penetrate the interior of the car without being dampened. The strength of the impairment of comfort depends on the magnitude of the pressure fluctuation (in Pa), the steepness of the pressure increase (in Pa / s) and the frequency of the events. Experiments with test persons in pressure chambers showed that pressure changes of more than 1000 Pa and pressure gradients of more than 2000 Pa / s can be perceived as disturbing.

Calculations by the Federal Railroad Central Office in Munich and the Minden Research Station showed that the values ​​are exceeded by far when driving through tunnels quickly, even without a train encounter. Therefore, a separate pressure upgrade for vehicles was required for the tunnel sections of the high-speed lines.

An indispensable prerequisite for pressure-proofing is permanently closed windows and thus equipping the affected cars with air conditioning. Non-air-conditioned compartment cars of the type Bm 235, which were still used in IC traffic at the end of the 1980s, were replaced by 140 newly built, pressure-capable cars of the type Bvmz 185 . Initially, 255 wagons of different types were made pressure-ready through conversion. By using special insulating rubbers around windows and doors, pressure-tight car transitions, pressure protection flaps, pressure protection fans and closed toilet systems, a system that is largely independent of external pressure influences can be achieved, which largely keeps the pressure fluctuations away from staff and travelers. Pressurized vehicles can be marked with (p) next to the vehicle address. On the other hand, vehicles with the identifier ) p (are only pressure-protected and therefore only have a safety package (this includes, for example, transition bridges secured against knocking up ), but otherwise no pressure-upgrading facilities.

For the construction of the ICE-1 trains, it was specified that the maximum external pressure change between +3900 and −5500  Pa , the permissible cabin pressure change, on the other hand, may only be ± 1000 Pa with a maximum pressure change of 200 Pa / s . These pressure fluctuations apply to a train encounter in the tunnel with a relative speed of 560 km / h, with the cross-sectional area ratio vehicle: tunnel being around 1: 8.

UIC Code 660 gives another recommendation for permissible pressure changes . In the 1994 version, it is recommended for high-speed trains to limit the change in pressure measured in hundredths of a second to 500 Pa / s and 1000 Pa per ten-second interval . The pressure or negative pressure behavior should be determined by experiment by exposing a single coach with active pressure enhancement devices to positive or negative pressure in order to measure the pressure drop with the air supply suspended for at least 18 s. The 2002 version also provides for a maximum pressure change of 800 Pa per three-second interval or 2000 Pa per 60-second interval. The UIC Code 660 also included the results of three-stage test subject examinations, which were carried out in 1989 in the Fulda – Würzburg section of the Hanover – Würzburg high-speed line .

While UIC Code 660 focuses on new railway vehicles for European high-speed traffic, UIC Code 779-11 defines pressure comfort criteria for tunnels. The permissible values ​​of the 779-11 can be understood as minimum requirements and are twice that of the Code 660.

The solution of making the vehicle pressure-tight reduces the fresh air supply to the occupants. There are two principal approaches in which it is attempted with

  • a) active systems to achieve a constant volume flow of fresh air and exhaust air. This is realized by pressure-protected fans that work independently of the pressure difference present, and
  • b) passive systems that dynamically lock the car only for the time of a pressure event. These are generally flaps in the air supply system that close the duct pressure-tight. The prerequisite for this method is that a pressure event has been previously detected or that it has been manually actuated (for example by the train driver). Typically, a pressure protection case is automatically detected at the tip of the train or carriage.

The activation of the print density can also take place via control and safety technology.

In Germany, vehicles that meet in tunnels at 250 km / h or faster trains must be pressure-protected in accordance with a decision by the Federal Ministry of Transport in 1996. According to the relevant decision, it is intended to exclude possible damage to health for certain groups of people that the railway medical service considers possible and to facilitate the use of the railway “by the disabled and the elderly as well as children and other people with usage difficulties”.

The largest pressure differences acting on the car body arise when trains meet in the tunnel. The pressure values ​​depend on the cross-section and length of the tunnel, the cross-section of the vehicle, the shape and length of the trains that meet and the speed at which they meet. Deutsche Bahn high-speed trains have to withstand the aerodynamic loads of encounters up to 330 km / h against 330 km / h in a tunnel with a cross-sectional area of ​​82 m² (status: 2002).

In addition to encounters between passenger and passenger trains, encounters between passenger and freight trains are also to be considered. Pressure loads from the head wave of fast moving passenger trains and flow loads from the freight trains' own speed act on freight wagons. Combined cargo transport containers , which made it necessary to reduce the pressure load when trains meet with passenger trains , proved to be critical . This made it necessary to reduce the speed of the ICE slightly.

Retrofitting of passenger coaches

Pressure-tight SIG wagon transition on a Finnish IC2 double-decker coach

The pressurization of a passenger coach requires a number of measures:

  • Replacement of the end sections of the car body by adapting and inserting new frames for entry and transition doors
  • Systematic sealing of the car body, e.g. B. of water drainage pipes
  • Creation of openings for new cables and pipes
  • Installation of pressure-tight exterior and intercar transition doors as well as pressure-tight bellows
  • Installation of closed toilet systems (with waste water tank)
  • Equipping the air conditioning system with pressure protection components

Finally, there is a leak test.

At DB in Germany and ÖBB in Austria , a large number of TEE and Eurofima wagons were retrofitted to make them pressure-sensitive. Some were also built as new buildings in order to be able to use them on the high-speed lines of the DB.

In order to be able to use the first new German routes Mannheim – Stuttgart and Hanover – Würzburg, which opened between 1988 and 1991, a total of 160 InterCity cars (21 first-class open seating cars “Apmz”, 37 first-class compartment cars "Avmz" and 102 second-class open-plan cars "Bpmz") of the German Federal Railroad at that time, ready for printing. Until then, the long-distance trains hauled by locomotives ran on the first completed section of the new line between Fulda and Würzburg at first only at 160 km / h, later at 180 km / h.

With the handover of the newly developed type Bvmz 185 IC cars on April 15, 1988, the former Federal Railroad also put the first pressure-ready series vehicles into service. After pressure-proof multiple units are almost exclusively used on the high-speed routes, the pressure-tight SIG wagon junctions have been replaced on numerous wagons with less maintenance-intensive rubber bead junctions. The affected wagons can still be recognized by the end signal lamps embedded in the corners of the wagon. Pressure-proof passenger coaches are also required for the trains of the " Munich-Nuremberg Express ".

Individual evidence

  1. ↑ a b c d Peter Diepen: Pressure upgrade of passenger coaches at the Deutsche Bundesbahn . In: The Federal Railroad . No. 4 , 1991, ISSN  0007-5876 , pp. 433-437 .
  2. ↑ a b c Provisions to ensure the technical compatibility of high-speed trains . 2nd Edition. August 2002, p. 13-15, 40 .
  3. ↑ a b Provisions to ensure the technical compatibility of high-speed trains . 1st edition. July 1, 1994, p. 18 f .
  4. ↑ a b Peter Deeg: 20-60610 Supplement to the statement on the aerodynamics of the STUTTGART-BRUCHSAL high-speed section, the new WENDLINGE-Ulm line and the new Stuttgart main station. (PDF) DB Systemtechnik , June 30, 2020, p. 9 f. (PDF) , accessed on August 2, 2020 .
  5. ↑ Monika Möller: High-speed routes for speeds over 250 km / h. (PDF) In: fahrweg.dbnetze.com. DB Netz, December 10, 2017, accessed on January 25, 2020 .
  6. ↑ Honestly: Train journeys at speeds between 250 km / h and 280 km / h. (PDF) E 15 / 32.31.01 / 139 EBA 96 (4). Federal Ministry of Transport, December 27, 1996, p. 2 f. , accessed January 25, 2020 .
  7. ↑ Ronald Hartkopf: Problems of mixed traffic on new lines . In: The Federal Railroad . No. November 11 , 1989, ISSN  0007-5876 , pp. 981-984 .
  8. ↑ a b Annual review 1988 . In: Die Bundesbahn 1/1989, p. 64 f.
  9. ^ The further plans of the new railway . In: Bahn-Special , Die Neue Bahn , 1/1991, Gera-Nova-Verlag, Munich, p. 78 f.