The Turkish Engineers and Architects Chambers Union (TMMOB) was informed about the accident that occurred on March 13 at the Eyüpsultan-Topçular stop, after a tram hit by a tram from the back, and then on March 15, at the Topkapı-Habibler tram line, derailing at the Topkapı stop. The Chamber of Mechanical Engineers (MMO) made a press release.
In the written statement, it was said that "The cause of the tram accidents is the desire to carry more passengers" regarding the tram accident where many citizens were injured.
Stating that the Istanbul Metropolitan Municipality (IMM) related to the accident could not explain the causes of the tram accidents that occur one day apart, MMO stated that the announcement made by the IMM could not go beyond giving information about the health status of the injured.
To explain the technical reasons of these two crash accidents and to inform the public and to take measures as a result of the task of transferring the rooms and the municipality of the MMO, shared some information about the accident with the public.
In the statement made by Ibrahim M. Tataroğlu, Secretary of the Board of Directors of Chamber of Mechanical Engineers of Istanbul Chamber of Mechanical Engineers, the information listed in 4 is as follows:
1) Trams do not pay attention to the voyage intervals and should not fall below the peak time application. The time interval for the trams is 90 seconds. That is, no tram should stop at the stop below the 90 seconds after the tram that precedes it. Each trolley that falls below the 90 seconds may derail or risk colliding with the tramway in front. In this context, the movement times of the trams should be rearranged and converted into a format that would not endanger human life. The lives of the workers or citizens should not be endangered in order to carry more passengers or carry out advertising in the style of 'the following passengers' before the elections of the municipal authorities.
2) There are 4 pieces of sand depots in 8 pieces in each tramway vehicle. Sand is of vital importance for stopping the emergency braking vehicle. At the moment of braking, the sand in the tank is sprayed between the rail and the wheel by means of pumps and the train is prevented from sliding or sliding. Control and monitoring of sand depots is vital.
3) Each trolley has 1 pcs 1 brake control unit computer. Tram cars operate independently of each other and only the cab used by the engineer is active and the other cabin is passive. In other words, the other trolley, which gives orders to the cabin, is taking orders. There is a mechanical connection and an electrical connection equipment called the kublaj which connects the tramway vehicles.
This is the electrical coupling coupling equipment that needs attention. Because these trams are managed from two different hosts and the connection between the electric coupling is the connection. These connectors are provided with copper contacts. These copper iron contact ends are oxidized over time, they are eroded, the ends are broken, mud and dust enter between them and there is no connection between the two trains. For example, when the front head rail is active, the front head (passive cab) will not listen to the order because the contacts do not transmit data, the front rail will not lower the rear wagon speed and push the front wagon. Such malfunctions are frequently encountered. This situation is the cause of accidents.
When the tram cars are loaded, braking distance increases according to the position of the vehicle. When a passenger is loaded with an emergency braking system, the braking distance increases due to the emergency braking of the tram car (this means that the vehicle is completely out of control of the driver when the truck is braked). This situation is a serious fault of the trolley.
4) Dynamic tests of tram cars should be carried out regularly every year.
Istanbul urban transportation officers should work with universities and professional chambers, especially urban planners. In the decision-making process of public investments, it is necessary to act with a human-centered approach that does not evaluate the views of professional chambers, universities and civil society, and abandons ler rantistic ve understandings that exclude science.
In order to prevent accidents, as Chamber of Mechanical Engineers, we inform the public that we will fulfill our responsibility and cooperate with the institutions and organizations in this field.