Attention everone! I have a major announcement to make! Haha friends, long time no see, I, oops, this blog has been half written since May last year, until I opened the draft box a few days ago and suddenly found, oops, I haven’t finished it yet Well, hey, take advantage of this time on Friday night to write it out quickly (from a student directly to a worker), this Friday, I am going to slow down my research work, air traffic, let's play together A different one, analyze the delay of the high-speed rail and the spread of the delay.
Solemnly explain: It’s still the same sentence. After the simple data collection work and the unserious analysis work, I have come up with a very unprofessional analysis report. I’m happy with the picture, so if there are professionals to come If you read it, I still hope that you will prepare first aid medicine in advance, don't be angry! Alright, the ramblings are over, and the text begins!
Solemn statement 2: my country's railway science and technology innovation has made historic achievements, the overall technical level has entered the world's advanced ranks, and some fields have reached the world's leading level. The integrated active safety prevention and control technology system of risk prediction, early warning and prevention and control has basically been formed. Significantly improved risk capacity. From 2008 to 2020, the average accident rate per 100 kilometers of my country's high-speed rail is 82% lower than that of overseas high-speed rail. As of the end of June 2021, my country's high-speed rail has safely operated 9.28 billion kilometers, equivalent to 232,000 circles around the earth, and safely transported 14.12 billion passengers. It is recognized as the safest high-speed rail in the world. Always have full confidence in China's high-speed rail! ! !
Summary
Due to its safety, efficiency, and convenience, high-speed railways are widely used in the rapid transportation of passengers and goods between cities. In order to improve the utilization rate and flexible turnover rate of trains, the high-speed rail EMUs have the characteristics of executing multiple lines and multiple shifts for one EMU in one day. When extreme weather or special circumstances occur, it will often lead to chain propagation of train delays. Both operations and passenger travel plans will have a serious impact. At the same time, if the traffic density of the operating line is higher, the impact on subsequent train delays will be greater. Therefore, this study takes the large-scale delay of Guangzhou South Railway Station on April 5, 2021 as an example to analyze the high-speed rail delay and its transmission chain. The delay time of high-speed trains on different lines is analyzed, and the delay chain trajectory is obtained; finally, the delay is analyzed according to the actual operation of the station and the configuration of the arrival and departure platforms, and the initial delayed vehicles and delayed lines are summarized. This paper proposes a case reference for improving the management and scheduling scheme of large-scale train delays in the high-speed railway sector.
Keywords: Delayed dissemination, unprofessional, casual look, just for fun
Fund project: This research was completed with the support of spicy hot pot, grilled cold noodles, potato chips, hot pot, Japanese food and Southeast Asian cuisine. During the research and analysis period, I would like to thank all kinds of milk tea and fat house happy water for my research Inspired, thanks to the charming teacher Guo and Guo Yan and Guo Yu for bringing me happiness, our king attacks Yesmola ! ! ! .
1. Background introduction
On April 5, 2021, due to the impact of the "red light belt" [1] on the downlink from Jianghai to Jiangmen East Station, the line was interrupted for 1 hour and 46 minutes. In addition, that day was the last day of the Qingming Festival holiday, and the passenger flow was large, and passenger trains showed high density. The characteristics of high-traffic operation have led to tight operation of the platform and lanes of Guangzhou South Railway Station, and the station's receiving and dispatching capacity has reached saturation, so the degree of subsequent train delays continues to expand.
[1] Red light belt is a technical term for railways. In the railway control system, the rails are used as conductors to form a track circuit, and the two tracks are shorted by the wheels of the train, which will be displayed in red in the control system to indicate the position of the vehicle. However, damp, insulation damage, lightning shock and other factors may cause the rails of the car-free section to be short-circuited, displaying an abnormal red light band or "flashing red", making it difficult for the console to judge the actual situation
2. Data source
The data comes from the train timetable, train delay information website, and 12306 website information. The data processing process is all manual, screenshot processing, and then manually input into excel for analysis.
3. Data analysis
3.1 Line operation
According to the analysis of the Weibo blogger’s travel line Toursline[2], the area where the red light belt occurred this time is located in the Guangzhou-Zhuhai Intercity Jiangmen Line. Therefore, in order to understand the operation of the line, this study first analyzes the complexity of the line and the number of trains running.
From the perspective of line complexity, in this operation section, not only the Guangzhou-Zhuhai intercity main line trains, but also the Jiangmen branch line and Jiangmen line trains merge and run together, and the line operation is relatively complicated.
From the perspective of the number of trains, according to the Passepartout train timetable data (not on the day, based on data on May 31, 2021), there are 66 trains on the Guangzhou-Zhuhai intercity main line (one-way), and 55 trains on the Guangzhou-Zhuhai intercity Jiangmen branch line. (One-way), there are 45 passenger trains on Guangzhan Railway, so there are 166 passenger trains (one-way) in this section throughout the day. Since the above lines basically do not arrange passenger trains to run at midnight, the daily operating hours are 6: 00-24:00 is a total of 18 hours. Therefore, on average, there will be a train passing through this line every 6 minutes (currently, it is known that the minimum departure interval of the high-speed rail line is 3-4 minutes).
To sum up, this section presents operation characteristics such as complex line design and high train density.
figure 1
figure 2
3.2 The situation of receiving and departing trains at the station
Since the delay started to spread gradually with Guangzhou South Railway Station as the trigger, this study will analyze the busyness of the Guangzhou South Railway Station platform and the incoming and outgoing trains.
According to previous research (note: see the statistics on platform usage in another article on my blog that analyzes the time-space pattern of ticket checking flow at busy high-speed rail stations), there are 28 lanes in Guangzhou South Railway Station, of which (20-28) lanes It is the platform of Guangzhou-Zhuhai Intercity Railway, Guangzhou-Shenzhen Railway, and Guizhou-Guangzhou High-speed Railway. (1-3 (uncertain)) lanes can connect Guangzhou-Zhuhai Intercity, and 20 lanes are shared by Beijing-Guangzhou High-speed Railway and Guangzhou-Zhuhai Intercity. Therefore, Guangzhou-Zhuhai intercity trains, Guangzhan railway trains, and Guizhou-Guangzhou high-speed railway trains need to share these 9 lanes for operation. As can be seen from the following two figures, the average utilization rate of ticket gates A2-3 and A20-28 is 41.1%, and the platform utilization rate is relatively high. In case of peak passenger flow such as holidays, the railway department will open additional passenger trains to meet the maximum travel needs of passengers. This case is the last day of the Ching Ming Festival holiday, and the short-distance travel demand in the province (such as Guangzhou-Zhuhai intercity) is often high during the Qingming holiday. Large, Guangzhou-Zhuhai Intercity, Guangzhou-Shenzhen-Hong Kong High Speed Rail, and Guangzhan Railway all responded to the blowout passenger flow by increasing the number of trains. Therefore, the Guangzhou-Shenzhen-Hong Kong Expressway, Guiguang Expressway, Guangzhou-Zhuhai Intercity, Nanguang Expressway, and The receiving and dispatching capacity of the Beijing-Guangzhou Expressway stations tends to be saturated. To sum up, during the holidays, the receiving and sending capacity of the platform is saturated, especially the multi-line shared platform poses great challenges to station scheduling and punctual train operation.
3.3 Analysis of train usage
Due to the high speed of high-speed trains and the convenience of vehicle maintenance, in order to improve the utilization rate of trains, the railway department will arrange for high-speed trains to be folded and set up. For example, the Beijing-Shanghai high-speed railway will start the G1 train to Shanghai at 09:00 in the morning Hongqiao, after the train arrived at Shanghai Hongqiao at 13:28 on the same day, it was directly prepared on the platform, and then the G4 train returned to Beijing South Railway Station at 14:00.
On that day, Guangzhou South Railway Station took Guangzhou-Zhuhai Intercity as an example (as shown in the picture below). From 6:00 am to 2340 pm, each Guangzhou-Zhuhai Intercity train runs an average of 12 round-trips. Return to Zhuhai, and return to Guangzhou South Railway Station immediately after stopping in Zhuhai for 15 minutes. Therefore, if the delay of the train exceeds the two stop thresholds, the next train will be delayed, and the delay chain will be generated.
3.4 Analysis of train delays
From the previous section, it can be seen that the density of trains at the station during the holidays is high, and the receiving and sending capacity of the platform is approaching saturation (hey, does it mean that the flow in our air traffic is close to the maximum capacity, well, let’s not discuss air traffic today. ), in this case, if a train is delayed for a long time, it will have a greater impact on the follow-up. Therefore, this section analyzes the train delays of Guangzhou South Railway Station on that day, and finds the delay nodes and delay chains. According to known information, train delays occurred only in the afternoon of that day, so the table below is an analysis of the trains arriving at Guangzhou South Railway Station in the afternoon (after 14:00).
| departure station | length of delay | number of trains |
| Zhuhai | 1:25:55 | 39 |
| Zhanjiang West | 1:03:43 | 28 |
| Shenzhen North | 0:36:25 | 22 |
| Nanning East | 0:18:17 | 18 |
| Chaoshan | 0:11:48 | 10 |
| Chengdu East | 0:11:42 | 10 |
| Guiyang North | 0:14:42 | 10 |
| Liuzhou | 0:04:30 | 10 |
| Kunming South | 0:09:40 | 9 |
| Yangjiang | 1:55:27 | 9 |
| North Sea | 0:08:51 | 7 |
| Changsha South | 0:27:51 | 7 |
| Fukuda | 0:06:30 | 6 |
| Wuhan | 0:11:40 | 6 |
| Chongqing West | 0:17:00 | 6 |
| Shantou | 0:10:12 | 5 |
| Nanchang West | 0:17:15 | 4 |
| Bose | 0:02:20 | 3 |
| Dali | 0:41:00 | 3 |
| Guilin North | 0:07:00 | 3 |
| Huaihua South | 0:03:20 | 3 |
| Maoming | 2:00:00 | 3 |
| Raoping | 0:30:20 | 3 |
| Yichang East | 0:23:40 | 3 |
| Yueyang East | 0:01:20 | 3 |
| Zhengzhou East | 0:34:00 | 3 |
| West of Beijing | 1:23:30 | 2 |
| Lanzhou West | 1:05:00 | 2 |
| Shanghai Hongqiao | 0:48:30 | 2 |
| Xi'an North | 0:15:00 | 2 |
| Bengbu South | 1:33:00 | 1 |
| Bijie | 0:00:00 | 1 |
| East Anton | 0:01:00 | 1 |
| Fangchenggang North | 0:15:00 | 1 |
| Fuzhou | 0:00:00 | 1 |
| Fuzhou South | 0:31:00 | 1 |
| Hankou | 1:16:00 | 1 |
| Hangzhou East | 0:11:00 | 1 |
| Hefei South | 0:10:00 | 1 |
| Huanggang East | 0:00:00 | 1 |
| Huidong | 0:02:00 | 1 |
| Jinan West | 0:32:00 | 1 |
| Lianyungang | 1:38:00 | 1 |
| Liupanshui | 0:54:00 | 1 |
| Luoyang Longmen | 0:07:00 | 1 |
| Meizhou West | 0:13:00 | 1 |
| Nanjing South | 0:00:00 | 1 |
| Qingdao | 0:00:00 | 1 |
| San Jiangnan | 0:05:00 | 1 |
| Shangrao | 0:00:00 | 1 |
| Wanzhou North | 0:10:00 | 1 |
| Xiangyang East | 0:01:00 | 1 |
| Xinhuang West | 0:00:00 | 1 |
| Xinyang East | 0:12:00 | 1 |
| Xing'an North | 0:03:00 | 1 |
| Xuancheng | 0:32:00 | 1 |
| Yibin West | 0:16:00 | 1 |
| Yinchuan | 1:09:00 | 1 |
| Indy West | 2:43:00 | 1 |
| Yongzhou | 0:00:00 | 1 |
From the table above, the stations with an average delay of more than one hour to Guangzhou are: Zhuhai, Zhanjiang West, Yangjiang, Maoming, Beijing West, Lanzhou West, Bengbu South, Hankou, Lianyungang, Yinchuan, and Yingde West.
Based on this result, we can propose two hypotheses:
1. The delay time is positively correlated with the number of trains in operation;
2. The delay time is positively correlated with the running distance of the train;
我们先来分析第一个假设：列车数量与延误时间的关系，首先将列车数量与延误时间用一个散点图来展示，表1为发往广州南站列车数量前十名的车站与延误的关系，从表中可以看出，发往广州南站的车次越多，导致的延误就越大，从这张图中看似假设1是成立的，但是，如果再分析第二张图，也就是所有发往广州南站的列车与其延误时间的关系，会发现其实列车数量与延误时间相关性并不是特别强，有时候有可能只有一班车发往广州南但是他的延误时间还是会很长。
因此，可以得出结论，假设1的表述是片面的，线路上列车数量只是加剧列车延误的一个诱因，但并不完全等同于列车数量越多，延误时间就越大，还要综合考虑线路的运行情况，车站的接发能力等因素。当然，如本案例，在广珠城际这种高密度运行、列车立折作业的线路区间发生了“红光带”故障，一定会导致延误的时间上升，因为首先该故障导致线路中断行车1小时46分钟，在这种列车高密度运行的线路里，一定会造成该线路后续列车的连续晚点（延误开始产生），同时，由于执行此线路的列车多为立折作业，到达延误势必会导致始发延误，造成延误的不断扩大。
同时对假设2进行分析，假设2描述列车运行距离越长，其延误的时间越长，这个假设也是根据上表2得出的，表2显示，由北京西、兰州西、蚌埠南、汉口、连云港、银川这些距离广州南站超过800KM的列车平均晚点时间均在1小时以上。但是，我们以北京西站为例，分析一下武汉（汉口）的车次,在相同距离（武汉站与汉口站的距离可忽略不计）的情况下，只有G1151,G4555这两趟列车出现了大于30分钟的延误，而其他车次并没有出现延误，尤其在当日16:00广州南站出现了一定程度的晚点以后，G1125,G1127两趟列车仍正点到达。
因此，可以得出假设2的结论也是不客观的，有时候，根据观察，延误传播是由点到面的向外扩散，因此，若是该列车运行距离越长，其受延误的波及就越小，当然这个要预先考虑比如说延误的处置及吸收速度，比如在列车还未驶入延误范围时或者列车的运行及整备速度大于延误的传播速度，则此论证成立。如果延误蔓延较快，延误程度较高，则会出现像G1151这样，长距离列车也出现延误的情况。
| 车次 | 始发站 | 终到站 | 预计到达时刻 | 实际到达时刻 | 延误时长 |
| G1151 | 汉口 | 广州南 | 21:59 | 23:15 | 1:16 |
| G1107 | 武汉 | 广州南 | 13:10 | 13:10 | 0:00 |
| G1109 | 武汉 | 广州南 | 13:15 | 13:15 | 0:00 |
| G1161 | 武汉 | 广州南 | 15:55 | 16:00 | 0:05 |
| G1125 | 武汉 | 广州南 | 19:21 | 19:28 | 0:07 |
| G1127 | 武汉 | 广州南 | 19:40 | 19:40 | 0:00 |
| G4555 | 武汉 | 广州南 | 23:55 | 0:53 | 0:58 |
3.5列车延误传播链式分析
对到达广州南站的列车延误情况进行分析（表4），首次出现长时间延误的列车为由佛山西开来的D7123次，延误时间为70分钟，其次是由阳江开来的C7226次，延误时间大约为61分钟，第三是由湛江开来的D7490次，延误时间大约为77分钟，第四为珠海开来的C7606次，延误时间约为13分钟。
同时，对广州南站始发列车延误情况进行分析，如下表5所示，首次出现始发延误的是开往湛江西的D7179次列车，其次是D7591。
表4
| 车次 | 始发站 | 终到站 | 预计到达时刻 | 实际到达时刻 | 延误时间 |
| D7123 | 佛山西 | 经停广州南终到茂名 | 14:17 | 15:27 | 1:10 |
| D3709 | 北海 | 广州南 | 14:19 | 14:19 | 0:00 |
| G1608 | 福州 | 广州南 | 14:19 | 14:19 | 0:00 |
| C7226 | 阳江 | 广州南 | 14:23 | 15:24 | 1:01 |
| G2935 | 昆明南 | 广州南 | 14:24 | 14:27 | 0:03 |
| C7686 | 珠海 | 广州南 | 14:28 | 14:41 | 0:13 |
| G6131 | 岳阳东 | 广州南 | 14:30 | 14:30 | 0:00 |
| D2809 | 贵阳北 | 广州南 | 14:35 | 14:35 | 0:00 |
| D7490 | 湛江西 | 广州南 | 14:39 | 15:56 | 1:17 |
| G1113 | 南京南 | 广州南 | 14:40 | 14:38 | -0:02 |
| D3789 | 南宁东 | 广州南 | 14:40 | 14:40 | 0:00 |
| G9543 | 新晃西 | 广州南 | 14:45 | 14:45 | 0:00 |
| D2811 | 毕节 | 广州南 | 14:47 | 14:47 | 0:00 |
| G85 | 上海虹桥 | 广州南 | 14:51 | 14:49 | -0:02 |
| C7606 | 珠海 | 广州南 | 14:52 | 15:05 | 0:13 |
表5
| 车次 | 预计开车时刻 | 终到站 | 实际开车时刻 | 延误时长 |
| D7473 | 13:24 | 湛江西 | 13:29 | 0:05 |
| C7219 | 13:29 | 阳江 | 13:31 | 0:02 |
| D2972 | 13:34 | 三江南 | 13:33 | -0:01 |
| G646 | 13:40 | 南昌西 | 13:39 | -0:01 |
| D7179 | 13:40 | 湛江西 | 14:58 | 1:18 |
| D3616 | 13:50 | 南宁东 | 13:50 | 0:00 |
| G6321 | 13:54 | 潮汕 | 13:54 | 0:00 |
| G544 | 13:56 | 郑州东 | 13:56 | 0:00 |
| C7675 | 13:56 | 珠海 | 13:56 | 0:00 |
| D212 | 14:00 | 贵阳北 | 13:59 | -0:01 |
| D3786 | 14:05 | 百色 | 14:05 | 0:00 |
| D7591 | 14:06 | 湛江西 | 15:05 | 0:59 |
| G6591 | 14:10 | 深圳北 | 14:41 | 0:31 |
关于延误链的源头问题，从仅有的数据中得出，开往茂名的D7123预计到达广州南时间为14:17，出现了延误，开往湛江西的D7179预计从广州南站发车时刻为13:40，也出现了延误，从时间上看，D7179次是本次延误的源头，但是需要注意的是，D7123是从佛山开来的列车，按照局内铁路运行的立折性(前序列车终到佛山，改车次为D7123佛山发车)，在执行D7123次列车运行之前应该有一班终到佛山西的列车，如果该列车正点，那么D7123才可能是延误链的源头，如果该列车到达佛山就是晚点状态，则延误链的源头应为D7123之前的这班列车。再结合当时线路发生故障的区域在广州南部下行线路，因此可以认为在广州南站的延误链源头列车大概率为D7179，BUT！如果发生线路故障导致的延误的话，应该是在线路上的列车而不是在站台上的列车为源头，因此，我们有往前查看时刻表，发现该线路在D7179之前发车的列车为D7473,D7471,D7187,由于发生的位置在阳江到江门之间，大约距广州南站1小时的旅程，因此可以认为，在D7179之前1小时左右发车的列车是延误链的源头概率最大，因此12:51发车的D7187，13:00发车的D7471这两趟列车是延误源头的概率最高（由于本人数据有限，无法直接分析具体是哪一辆车）。
3.6延误传播范围分析
在上一节中提到，延误是有一定的传播速度及传播范围的，本节对广州南站到达车次的延误情况进行分析，提取延误传播范围。
表6
| 时间段 | 发生延误的线路及车站 |
| 1300-1400 | Guangmao Line, a small number of downlink stations between Guangzhou South and Zhanjiang West |
| 1400-1500 | Guangmao Line, the station between Guangzhou South and Zhanjiang West |
| 1500-1600 | Guangzhou-Zhuhai Intercity, Guangmao Line, stations between Guangzhou South to Zhuhai and Guangzhou South to Zhanjiang West |
| 1600-1700 | Guangzhou-Zhuhai Intercity, Guangmao Line, stations between Guangzhou South to Zhuhai and Guangzhou South to Zhanjiang West |
| 1700-1800 | Guangzhou-Zhuhai Intercity, Guangmao Line, stations between Guangzhou South to Zhuhai and Guangzhou South to Zhanjiang West |
| 1800-1900 | Guangzhou-Zhuhai Intercity, Guangmao Line, stations between Guangzhou South to Zhuhai and Guangzhou South to Zhanjiang West |
| 1900-2000 | Guangzhou-Zhuhai Intercity, Guangmao Line, stations between Guangzhou South to Zhuhai and Guangzhou South to Zhanjiang West |
| 2000-2100 | Guangzhou-Zhuhai Intercity, Guangmao Line, stations between Guangzhou South to Zhuhai and Guangzhou South to Zhanjiang West |
| 2100-2200 | Guangzhou-Zhuhai Intercity, Guangmao Line, Nanjing-Guangzhou High-speed Railway, Guangzhou-Shenzhen High-speed Railway, Guangzhou South to Zhuhai, Guangzhou South to Hengyang, and Guangzhou South to Zhanjiang West |
| 2200-2300 | Delays start almost across the board |
| 2300-0000 | Delays start almost across the board |
According to Table 6, there are three important time nodes in the delay propagation range, 1300-1400 is the node that starts to spread on the main line (Guangmao Line), 1500-1600 the delay spreads to the Guangzhou-Zhuhai intercity, between 1500-2100, the delay It did not continue to spread, but was fixed between these two lines. At 2100, the delay began to spread to the Guangzhou-Shenzhen-Hong Kong High-Speed Rail and the Nanjing-Guangzhou High-Speed Railway. After 2200, almost the entire line of Guangzhou South Railway Station was delayed.
4. Summary
The first thing to say is that this analysis is only inferred from my existing data, and the conclusion and the actual tolerance are large, and it is only for entertainment analysis. Secondly, the temporary stop of the railway at the first moment of failure ensures the absolute safety of passengers, which cannot be disputed. Third, Guangzhou South Railway Station is one of the busiest high-speed rail stations in my country. It is conceivable that the high complexity of train scheduling and the high difficulty of traffic organization. The impact will also become smaller and smaller.
Finally, it’s finally the end. I still hope that everyone can find the research points they are interested in~
In the next issue, uh uh uh I’m going to write a bit about the macro basic map to analyze the arrival and departure of trains at the station, but this still depends on the follow-up time, or talk about the prediction of the airport acceptance rate (AAR), hey, after all this AAR has really bothered me for a long time, and there is still a paper to be published. I still don't quite understand whether this AAR is capacity or traffic. How about air traffic flow? Hey, this air traffic flow is really a good thing.