Turn order
The term train sequence used in colloquial language , often synonymous with train sequence time , describes in this sense the time interval between two trains traveling one behind the other .
In traffic science , the terms train sequence and train head time are strictly separated from each other.
In terms of traffic science, train sequence is the sequence of trains (generally: transport units) on a certain route or at a certain location, which is usually prescribed or specified in the timetable.
Train headway, on the other hand, is the time interval between departure, arrival or passage of successive trains at a station or on the route ( route-train headway ), measured at the same location.
Train sequence according to the timetable
The train sequence according to the schedule provides information on how busy a train route section is and can vary depending on the time of day. In many urban railways ( S-Bahn , U-Bahn ), a very dense train sequence in the rush hour in the morning and in the late afternoon, a less dense train sequence at other times of the day and a heavily thinned train sequence at night is common in order to allow the use of vehicles (and thus the Operating costs) to the daily fluctuations in demand, the so-called daily curve . This size can also be used to count traffic in rail traffic , for example by precisely counting the number of passengers on a train and then multiplying it by the hourly number of trains to get the number of passengers per hour. It is roughly comparable to the density of vehicles on the road .
Minimal sequence of moves
The minimum possible train sequence depends on the structural conditions, in particular the signaling equipment of the route. In the case of railways according to EBO , subways and sections of trams secured by signals (both according to BOStrab ), the route is divided into block sections, at the beginning and end of which there is a signal. In each of these block sections (apart from malfunctions and shunting trips) there may only be one train in order to prevent rear-end collisions. The entry of the next train into a block section is only released by a corresponding signal aspect when the train in front has completely cleared the block section (as well as a short section behind the target signal, the slip path , which is intended to prevent rear-end collisions if the target signal is accidentally driven over with subsequent emergency braking ) Has. A shorter train sequence therefore requires shorter block distances and thus shorter signal distances.
Shortening the sequence of moves
The shortening of the signal intervals, however, both for cost reasons and for practical considerations (block sections are shorter than the braking distance of a train, too many signals, so that a driver can no longer safely perceive the signal that is currently valid for him without getting confused) quickly Limits so that train sequences of less than 2 to 3 minutes with conventional signals are difficult to implement. One possible way out are multi-section signals , which signal not just one but several of the following block sections. They thus enable the vehicle's speed to be adjusted and ensure sufficient braking distances without the driver having to perceive and remember several signals or too many signals in a short time. However, since limits will soon be reached here too, a further consolidation of the train sequence is only possible with systems for driver's cab signaling , which enable permanent communication between the signal box and the traction vehicle via continuous train control ( e.g. via LZB line managers, radio with ETCS Level 2 or rails TVM ) and always display the current maximum speed in the driver's cab, as well as information on upcoming braking processes, so that the driver no longer has to pay attention to trackside pre- and main signals .
Driver's cab signaling also enables the trains to run automatically with a driver (e.g. automatic travel and brake control ), and also fully automatic operation without a driver (e.g. line U3 of the Nuremberg subway ), through constant communication between the vehicle and the signal box In addition to the shortened train sequence, there are also economic advantages by reducing the number of drivers.
Closest train sequences in Germany
Closest train sequences in the signal-secured EBO area
As early as the 1936 Summer Olympics, after the introduction of the Sv signal system, the Berlin S-Bahn was running every 90 seconds (40 trains per hour and direction); this was also made possible by the lack of a slip path behind exit signals.
Signal systems developed later shortened the train path sections (block sections), since in Germany not using slip paths does not correspond to the recognized rules of technology . This was achieved by the fact that the respective block section but one counts as a slip path for the following block section. However, it is still permissible to shorten the slip path behind exit signals at platform ends to a distance of up to 2 m if the decisive protection point is the end of the train in front and the next signal is at least 210 or 260 meters ( S-Bahn Berlin or S- Bahn Hamburg ) away.
The scheduled closest train sequence of a railway line according to EBO has been in Germany since 2004 on the main route of the Munich S-Bahn , where after equipping the route with liner train control with CIR-ELKE (modified) a scheduled train headway time of 120 seconds is achieved at peak times (30 trains per hour and direction). The technically possible minimum train headway time is 96 seconds (that's 37.5 trains per hour and direction), originally even 90 seconds (40 trains per hour and direction) were required.
Closest train sequences in the signal-secured BOStrab area
The closest train sequence to BOStrab is on a subway line on the main route of the U2 and U3 lines of the Nuremberg subway , where driverless operation is possible with a train headway time of 100 seconds (36 trains per hour). Shortly after the U2 line was switched to automatic operation, however, there were a number of disruptions, so that operations at 100-second intervals were temporarily suspended.
In the SelTrac trial operation of the Berlin U4 (1981–1993), technical headway times of 50 to 90 seconds were even achieved.
Closest train sequences in the non-signal-secured BOStrab area
Trams run on sections of the route without signals on sight and can therefore, depending on the system parameters (e.g. double stop ), follow one another even closer than the previously technically possible 50-90 seconds.
Operational information
When specifying the times of today's applications, it must be taken into account that it is the shortest scheduled train headway time, which basically contains reserves ( buffer times ) in order to absorb various random influences and also to be able to reduce minor delays. The minimum technically feasible train headways are therefore significantly shorter, but for reasons of stability they cannot be realized over longer periods of time with several trains; otherwise, random influences would cause the trains to jam.
The shortest possible train headway time for a certain route section is also mathematically dependent on train length, maximum speed, acceleration and braking behavior, securing the train sequence , signal system , train control system , driving regulations, other operational regulations, as well as passenger switching and handling times and can be determined with the help of methods of Calculate operating theory .
Closest train sequences in Switzerland
Closest train sequences on signal-secured standard-gauge railways
On the long - haul routes in the Swiss core network, especially on the new Mattstetten – Rothrist line, several InterCity and InterRegio trains run immediately after each other every two minutes.
Individual evidence
- ^ Transpress Lexikon Eisenbahn, Transpress VEB Verlag für Verkehrwesen, Berlin, 1972, p. 786
- ↑ transpress Lexikon Stadtverkehr, Transpress VEB Verlag für Verkehrwesen, Berlin, 1985, p. 484
- ^ Siegfried Rüger : Transport technology urban public transport. Transpress VEB publishing house for traffic; Berlin 1986 (3rd edited edition), p. 29 ff.
- ↑ Oliver Zauritz: The Stadtbahn: A brilliant achievement of the engineers. In: Punkt 3 , 11/2011, p. 11.
- ^ Peter Bley: Berlin S-Bahn. alba Verlag, Düsseldorf 1997 (7th edition), p. 106.
- ^ Hans-Jürgen Arnold et al .: Railway Safety Technology (2nd edition). transpress VEB Verlag for Transport, Berlin 1974, p. 431.
- ↑ Guideline 819 “Planning LST Systems”. Module 819.20 "Design of the safety systems of the DC-operated S-Bahn Berlin and Hamburg"
- ↑ Bavarian State Ministry for Economic Affairs, Infrastructure, Transport and Technology: Answer of April 20, 2010 to a state parliament request of February 1, 2010. in: Printed matter 16/4700 of June 8, 2010, Bayerischer Landtag, Munich 2010, p. 3.
- ^ A b Klaus Hornemann: Line train control on the Munich S-Bahn. In: Eisenbahn-Revue International 6/2006, Minirex Verlag, Luzern 2006, p. 306ff.
- ↑ Automatic subway is slowed down. Archived from the original on January 24, 2010 ; Retrieved June 15, 2010 .
- ↑ Mark Jurziczek v. Lisone: The SelTrac test farm . In: Berlin traffic pages. 2010, accessed December 2, 2011 .
- ↑ Federal Office of Transport: Official Course Book 2012. FOT, Bern, 2012