Thursday, 7 March 2019

Technical talk over the station accident





I know it is repeated talk… I also know that the worst evil in our country these days is the alleged ability of everyone to diagnose what we are going through. Also the audacity of some to prescribe the medication that usually – or always – has this form we used to know in the past, when we were told in our folk stories about that prescription that used to cure headaches and worms in intestines; that liquid that we did not know its composition and whose sellers used to stand at the corners of public squares and Mawaled’’s yards to sell it. However, I will take the risk and write about this topic, for we may come up with something new!

I here mean the accident of the railway station, which came as an answer for a question that for long occupied my mind when I use the train coming from Tanta or Alexandria to Cairo. I used to see the concrete stopping bumps at the end of the railway platform and wonder: to what extent can these bumps withstand the collision of a train? It also never occurred to me to figure out the speed of the train colliding with it, for I have not imagined that a train may enter the station at an 80 km/h speed!

In such context, I publish what my friend Mr. Mounir Ayyad sent to me in a stating message; meaning it may be right or wrong. I cannot confirm its veracity. He himself got it from Mr. Email Attallah; trainer of railway trains’ drivers in New South Wales for more than 20 years: “There is a very very big question mark regarding the catastrophe that took place in Bab el-Hadid in Ramsis square;

1- Any train coming close to a concrete or iron stopping bump should have a speed of 25 km/h at a distance of 500 meters away from the bump; otherwise it will lose the brakes’ air and will stop forcefully.
2- The train’s speed when it comes in friction with the beginning of the 160-meter-and-more-long platform has to decrease to 5 km/h; otherwise the ground bumps will empty it of the air and it will stop immediately in less than 3 seconds.
3- The closer the train to the bump, the less the speed that decreases every 30 meters until it forcefully reaches zero at the bump; otherwise the train will be forcefully stopped not less than 20 to 40 meters away from the bump.
4- Even if the train’s bumps collided with the ground bump, there is a spring that can withstand pressures huge enough to make the stopping action smoother and not harmful.

What happened was an accumulation of terrible failures including:
1- Not having safety systems; if one of those safety systems dropped, the train or carriage is banned from being used in service.
2- There are three safety systems in the old trains; (dead man feature, control governor and main blunger), while there are four in modern ones. Such thing makes this accident almost impossible, and the probability of it happening is not more than zero percent.
3- Even if the driver was asleep, dead or drugged, the train itself will come to stop once the driver’s muscles relax. Therefore, I do not care much about the status of the driver, unless there is a very bitter probability that I will tell later.
4- Even if we assumed that the train itself –including the antenna, electrical and power controls– totally and utterly failed, the ground control network adjacent to the railway bars, including the air compressor, will stop the train anyway once it exceeds the legal speed determined gradually to be 3 to 5 km/h. Also, even if we assumed that the train failed and the railway bars’ control system failed, the signals’ control system cannot fail, as the signal does not allow the train to pass unless the speed was very close to the legal one in case of high speeds over the main routes, and which decreases over the routes connecting the sub-urbans. The same thing applies over the domestic routes. Then the speed reaches 25 km/h in case of getting close to a dead end.

Conclusion:
What happened was a complete circle of failure including the following:
1- The train system itself (consisting of 3 or 4 safety systems).
2- The railway routes’ system (consisting of unlimited number of safety units adjacent to the left or the right of the railway bars) depending on the air compressor position.
3- The signals’ system; as each signal is supplied with a safety unit.

If one system of the mentioned above failed, that means we are facing a catastrophe that can have no explanation but with the following:
(An agreement between the driver to disable all the train’s safety devices with the worker supervising the railway ground connections to make it corrupt, in addition to the approval given by the signals’ box or signals’ computer to break the closed signal, in the same time, spoiling the signal’s safety system. The last one alone needs a pre-agreed upon effort which is very big”.

The stating message ended for the big question to rise.
We shall continue later.

Translated by: Dalia Elnaggar

This article was published in Al Ahram newspaper on March, 7, 2019.

To see the original article, go to:

#ahmad_ahmed_elgammal #Egypt #railway_station_accident

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