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(11) | EP 3 617 033 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 153(4) EPC |
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| (54) | METHOD FOR CONTROLLING UNDERGROUND RAILWAY LINES |
| (57) A metro traffic management method wherein wagons do not stop at each station and
no wagon overtakes other wagons. In the claimed method, wagons travel in 1, 2, 3,
4 mode, meaning that a wagon stops at the next station, then skips one, then skips
two and finally skips three stations to stop at the fourth station. Then the 1, 2,
3, 4 cycle is repeated. The object of the invention is to (a) increase the throughput
capacity of metro lines; (b) reduce trip times and (c) achieve savings of electricity. |
Technical field:
[0001] This invention relates to a metro traffic management method wherein wagons do to not stop at each metro station and no wagon overtakes other wagons.
[0002] The object of the present invention is to (a) increase the throughput capacity of metro lines, (b) reduce trip times, (c) achieve savings of electricity and (d) reduce the physical wear of metro vehicles (especially of their braking systems).
Background art:
[0003] Presently, metro wagons are coupled in train consists and travel as full consists (one consist is made typically of three or four wagons). These train consists stop at each and every station. When passengers board a train consist, they do not need to mind which wagon they go in because all wagons go to the same places.
[0004] This is largely inefficient, especially in the case of long metro lines with many stations and short distances between the stations. In this case, much of the time of the passenger who travels to a long distance is wasted in unnecessary halting at interim stations.
[0005] The method which most closely approximates this invention is [1], published by this author on 3 December 2015 and its subsequently published variations [2-5]. The main difference between the methods [1-5] and the method presented in this patent is that here wagons travel without overtaking each other, conversely to [1-5] where overtaking does take place. This is exactly why the methods [1-5] have only theoretical relevance, and are practically inapplicable, while the method in the present patent is perfectly applicable in real subway systems.
Gist of the invention:
[0006] Each wagon travels in 1, 2, 3, 4 mode. This means that the wagon first stops at the first station, then skips one station, then skips two stations, and then skips three stations, and then repeats the 1, 2, 3, 4 cycle.
[0007] Thus, each wagon stops at only 4 of the next 10 stations, meaning that the number of start-stop cycles is reduced by factor of 2.5.
[0008] For each wagon we must count 1, 2, 3, 4 in order to know at which step of the 1, 2, 3, 4 cycle it is now. Furthermore, we must count the wagon's stations in order to know at which station it has to stop. Each wagon depicted in Figures 1 and 2 is tagged with the values of the these counters in (X:Y) format. For example, the blue wagon (4:4) in Figure 1 is just departing from the red platform of the station and will only need to stop at the fourth station. Wagon (4:4) is followed by another blue wagon (4:3) which will skip this station plus two more stations and will only stop at the third station (from this perspective it will stop at the third station, but from the perspective of the previous station, i.e. the station of departure, it will stop at the fourth station).
[0009] Let us take a random point A in the metro line. Let us have a wagon which has departed from the station immediately before point A and will stop at the station immediately after point A. Thus, the values of the counters of that wagon at point A are (1:1) and the wagon is at step 1 of the 1, 2, 3, 4 cycle. The next two wagons to pass by point A will be at step 2 and the values of their counters will be (2:2) and (2:1), respectively. The next three wagons will be at step 3 and the values of their counters will be (3:3), (3:2) and (3:1), respectively. Finally, four other wagons will pass by point A - they will be at step 4 and the values of their counters will be (4:4), (4:3), (4:2) (4:1), respectively. Once these 10 wagons pass by point A, the sequence will be restarted and the next wagon will be (1:1).
[0010] Thus, based on the values of their counters, the wagons pass by point A in the following order:
(1:1), (2:2), (2:1), (3:3), (3:2), (3:1), (4:4), (4:3), (4:2), (4:1).
[0011] Only the wagons whose second counter is 1 (one) stop at the next station. So, only four of the ten wagons stop at that station. The other six wagons proceed without stopping at the station.
[0012] While the order in which the wagons travel is important, equally important are the exact places at which they stop.
[0013] The station platform is divided in four smaller platforms (sub-platforms, Figures 1 and 2). Only one wagon at a time can stop at a sub-platform. The length of the wagons is around one-fourth of the length of the full train consist which can be accommodated at the full platform (i.e. at the four sub-platforms).
[0014] The first sub-platform is reserved for wagons which will skip the next two stations and stop at the third one. (The first sub-platform is the rearmost in downstream direction, i.e. the direction in which the wagon is headed). Accordingly, the second sub-platform is reserved for wagons which will skip three stations to stop at the fourth one. The third sub-platform is wagons which will skip one station and stop at the second one. Finally, the fourth platform (the first one in downstream direction) is reserved for wagons which are due to stop at the next station.
[0015] The four sub-platforms are numbered 3, 4, 2, 1 in downstream direction and are colour-coded in yellow, red, blue and green, respectively. With this colour-coding system, green is the sub-platform for wagons whose next leg is the shortest (to the next station). Red is the platform for wagons whose next leg is the longest (i.e. to the fourth station counted from the station of departure).
[0016] Passengers must be mindful of which sub-platform they board a wagon. The station of destination determines the right sub-platform of departure. To help passengers choose the right sub-platform, at each station there is a passenger information board (Figures 2, 3 and 4) with metro stations shown in the colour-coding system used for the sub-platforms. The next table illustrates the content of these passenger information boards:
| Station: | Colour of the circle(s): |
| The station at which the board is installed | White |
| First downstream (next) | Green |
| Second | Blue |
| Third | Yellow, green |
| Fourth | Red |
| Fifth | Red, blue |
| Sixth | Green |
| Seventh | Yellow, red |
| Eighth | Yellow |
| Ninth | Blue |
| Tenth | Green, red, yellow, blue |
[0017] Each station is represented by an appropriately coloued circle. Where the colours are two or four (meaning that two or four sub-platforms are possible for departure to that station), the station is represented with two or four partially overlapped circles the uppermost of which has the colour of the sub-platform at which a wagon will arrive first. Thus, the information on the board is dynamic rather than static, because it needs to show which one of the possible wagons will be the first to arrive. Accordingly, in order to reflect this dynamic information, the board is electronic rather than paper-based.
[0018] The board after the 10th station follows the same pattern (the 11th station is coloured as the first, and so on). The colours of the board in the opposite direction are exactly the same (station -1 is coloured same as station 1, and so on).
[0019] The appearance of the board is specific to each station. The next station (the first downstream station) is always represented by a green circle, however, vis-à-vis other locations a station may or may not be the first one. In Figures 4 and 5, Serdika Station is green on the board at Opalchenska Station, because when seen from Opalchenska it is the first one after it. The board at Konstantin Velichkov Station shows Serdika in blue, because from the perspective of Konstantin Velichkov it is the second one.
[0020] It can be seen from the above table that for each station there is at least one wagon which goes to that station so that passengers do not need to change wagons in order to reach the station of destination.
[0021] The method can be adjusted to a different number of sub-platforms, e.g. 3 or 5. In the case of 3 sub-platforms, each wagon travels to a scheme of 1, 2, 3. This means that 3 wagons will stop at each station and other 3 wagons will skip that station. Thus, the number of stops is reduced by a factor of 2. In the case of 5 sub-platforms, each wagon travels to a scheme of 1, 2, 3, 4, 5. This means that 5 wagons will stop at each station and other 10 wagons will skip that station. In this case the number of stops is reduced by a factor of 3.
[0022] The fact that 4 out of 10 wagons stop at a station and 6 wagons skip that station is one of the reasons why the claimed method increases the throughput capacity of metro lines. The second factor is the arrangement of the wagons and of the sub-platforms (the places at which the wagons stop). This arrangement ensures that three wagons can stop at a station at the same time. These are the wagons with counters (4:1), (1:1), (2:1). Wagon (2:2) would be forced to stop together with them. Therefore, (4:1), (1:1), (2:2) and (2:1) can all stop at the same time. Once these wagons pass the station their counters will acquire the values (1:1), (2:2), (2:1), (3:3), respectively: for the wagons that have stopped, the first counter will change its value and the second counter will acquire the same value as the first counter, while the only change for the wagons that have not stopped will be a reduction of the second counter value by one. Thus, at maximum load conditions, it takes two halts to let ten wagons pass through the station - once three wagons and once one wagon. If the traditional traffic method is used, the station would be served by 10 wagons arranged in two and half train consists (4 wagons per train). This makes two and half stops instead of two.
[0023] The new traffic management method reduces the number of interim stops by 2.5 times and thereby shortens the trip time. On the other hand, the waiting time at the stations is increased by 2.5 times. This means that the new traffic management method is time-efficient in heavy traffic conditions when intervals between the wagons are brief and waiting times are limited. Conversely, in light traffic conditions, when the wagons in service are less and waiting times are longer, the new traffic management method is inefficient and leads to longer trip times.
[0024] For this reason the traffic management method is operated in two modes. The first mode is the one described above and will be used in heavy traffic. In light traffic mode, the wagons stop at all stations at which passengers are about to leave or board the wagon. The light traffic mode reduces waiting times by a factor of four, because each station is served by 4 individual wagons rather than by one train of four wagons. In this mode the wagons do not skip stations unless no passenger has indicated that he is due to leave or board the wagon. This indeed is a frequent situation because (a) in light traffic the number of passengers is limited and (b) the train consist is divided in four wagons (so the expected number of passengers leaving or boarding the wagon is four times less).
[0025] Only two of the sub-platforms are used in the light traffic mode. Typically, these are the foremost and the rearmost, or the two in the middle depending on the location of the station gates.
[0026] In the light traffic mode there are two types of wagons: those that stop only at front sub-platforms and those that stop only at rear sub-platforms. Thus passengers know that when they board from the front sub-platform they will disembark at the front sub-platform, similar to the existing method: passengers do know that when they board a front wagon they will disembark from a front wagon too. The wagons travel in an alternating order - one due to stop at front sub-platforms and one due to stop at rear sub-platforms. This ensures that two wagons can stop at a station at the same time.
[0027] Important is the procedure to switch between the two modes. The new mode applies only to the wagons leaving the first station on the line while the wagons en route follow the previous mode until they reach the terminal station.
Description of figures
[0028]
Figure 1. This figure shows Konstantin Velichkov Station and two blue wagons headed to the right. Another red wagon has departed from the yellow sub-platform and is headed left (now it is between the red and the blue sub-platforms). The topside shows a larger stretch of the line (in smaller scale).
Figure 2. This figure shows Opalchenska Station. Blue wagons travel to the right and red wagons are headed to the left. The blue ones (1:1) and (2:2) have just departed from the green and respectively from the blue sub-platform. The red wagon (4:0) is grinding to a halt at the green sub-platform. When this wagon departs, its counters will be (1:1) because step 4 is followed by step 1.
Figure 2 also shows the passenger information board which directs passenger to the sub-platform they need to use.
Figure 3. This figure shows again Opalchenska Station and the same passenger information board on a larger scale.
Figure 4. Again, this figure shows Opalchenska Station and the same passenger information board on an even larger scale so that station numbers and names can be seen.
Figure 5. This figure shows again Konstantin Velichkov Station and the passenger information at that station which looks different than that at Opalchenska. The time in Figure 5 is six seconds behind the time at Figure 1. The blue wagon has not departed yet and the red wagon is still by the yellow sub-platform from which it has just departed.
Examples of embodiment
Example 1.
[0029] Let us have a metro line where stations are 1 200 meters apart. Let the trains travel at 20 m/s (72 km/h). Let the acceleration/deceleration rate be 1 m/s2. Let the trains stay at each station for 10 seconds on the average.
[0030] In this setup, each needless stop is a waste of 30 seconds (10 seconds to halt, 10 seconds to stay and 10 seconds to depart). At a traveling speed of 20 m/s, it takes 60 seconds to go from one station to the next one. In this scenario, therefore, one-third of the time will be lost in halts. With the metro management method claimed here, the number of interim stops is reduced by 2.5, which means that from 10 stations we do not stop at 6 of them. This translates in time savings of (6/10).(1/3)=20 %. Note that with the same number of wagons waiting times will increase twice (it will be not 2.5 times more because the wagons will travel 25 % faster), so it can be assumed that the average time saving achieved will be in the region of 10 %, assuming that the waiting time is 1/10 of the traveling time. This is possible when the wagons are frequent (e.g. at one-minute intervals) and the traveling distance is more than one station. If the traveling distance is one station then we do not save time. Conversely, we will spend more time as waiting at the station platform will take twice as long.
[0031] Let us assume that half of the electricity consumed is spent on stops and starts, and the other half is spent on keeping the vehicle going at a constant speed. Thus, reducing the number of stops by a factor of 2.5 leads to electricity savings of 30 %.
[0032] Now let us calculate by how much the throughput capacity of the metro line will be increased. Assuming that each wagon is 20 meters long, a train consist of 4 wagons will need ca. 18 seconds in order to start and halt within 80 meters. Then we add 10 seconds of station time and conclude that it takes at least 28 seconds for 4 wagons to go through. 10 wagons will go through in 70 seconds (28 × 2.5).
[0033] With the new metro management method, at maximum load conditions there will be two stops for 10 wagons. The start and halt distance is 80 meters for the first stop and 120 meters for the second stop. This makes 18 plus 22 seconds. Add 2 × 10 seconds of station time. The result is that 10 wagons at maximum load will go through in 60 seconds, i.e. the new metro management method increases the capacity of the metro tube by around 17 %.
[0034] This discussion does not factor-in the presumption that with less wagons stopping at the station (one or three instead of four), the time they spent at the station should be less. Therefore, the expected capacity improvement may even exceed 17 %.
[0035] Another factor which is not accounted for is that with the new management method the number of passengers leaving and boarding the wagons will be 2.5 times higher. While the proportion of passengers leaving the wagon in the traditional method is 10 %, now 25 % of the passengers head to the doors. This suggests that vehicles may stay at stations longer because there will be more people getting off and on. On the other hand, in a crowded wagon those who are not disembarking stand in the way of those trying to leave, so 25 % might disembark in roughly the same time as would 10 %.
Field of application (use) of the invention
[0036] The present metro traffic management method is appropriate for automated metro systems. The method is not appropriate for metro systems relying on manned vehicles, because it requires four times as many train drivers. Furthermore, the present method is conducive to higher densities and shorter distances between vehicles, which make manned metro vehicles more prone to accidents.
References
[0037]
- 1. Metro where every wagon has its own opinion (Beta 1), a computer program, 3 December 2015, http://www.dobrev.com/software/Metro_b1. pro
- 2. Metro where every wagon has its own opinion (Beta 2), a computer program, 10 December 2015, http://www.dobrev.com/software/Metro_b2. pro
- 3. Metro where every wagon has its own opinion (Beta 3), a computer program, 18 January 2016, http://www.dobrev.com/software/Metro_b3. pro
- 4. Metro where every wagon has its own opinion (Beta 4), a computer program, 26 March 2016, http://www.dobrev.com/software/Metro_b4. pro
- 5. Metro where every wagon has its own opinion (Beta 5), a computer program, 5 April 2016, http://www.dobrev.com/software/Metro_b5. pro
1. A metro traffic management method with wagons not stopping at each station and no
wagon overtaking other wagons, wherein wagons travel in 1, 2, 3, 4 mode, meaning that
a wagon stops at the next station, then skips one, then skips two and finally skips
three stations to stop at the fourth station, and then repeats the cycle.
2. A metro traffic management method as in claim 1, wherein in less intense traffic we
alternate the 1, 2, 3, 4 mode with a mode where wagons stop at all stations at which
passengers are due to board or leave the wagon, and when traffic becomes more intense
we switch back to the 1, 2, 3, 4 mode.