This text was prepared by Gökce Aydin
TMİ stands for “Telefonla Merkezden Idare”. It is a type of manual traffic control using written train orders. The system is operated by local stations but regulated by a line dispatcher.
In TMİ system, dispatcher works in a centralized office. He constantly watches the current train traffic by means of tabular data sheets of train traffic and also traffic diagrams. He prepares the appropriate solutions for the traffic regulation and calls the local operators (local station staff) to transmit the orders. The local station staff repeats the order back to the dispatcher and then the order becomes valid. The local station staff prepares written orders from the orders they take from the dispatcher and hand them to train crews. Trains are allowed to exit from a local station area only if they get the appropriate order to depart. Local operators are also responsible for calling the dispatcher and inform the dispatcher about departure and arrival of trains from/to their stations. By this way dispatcher is able to watch the traffic. And he regulates the passing/overtaking operations accordingly.
In TMİ system, trains can follow each other at station distance. This means that, a train is only allowed to depart from a station when the preceding train arrives at the next station and clears the entrance to the next station. This absolutely doesn’t lead to a high capacity of line and the system is used in the lines having a relatively low traffic density. It is very safe however.
TMİ system is sometimes combined with a (mechanical) signaling system. But the signals are only provided at the entrance and exit of the interlocking areas, there are no intermediate block signals. So, the principle of train separation by station distance still applies in such lines. On such lines, the signals are mainly used to tell the driver that he has to stop at the station and collect a new order. It may also tell the driver to stop the train before entering the station. Also, the signaling system means that an interlocking system is set up within the station and leads to an increased safety and flexibility. If there is no signaling system, the situation is shown to the train crews by means of green or red flags. In such lines, driver has to approach the station at such a low speed that he may stop the train before entering the station. Also the driver cannot know whether the route set is straight or diverging, and he has to pass the entrance points at a reduced speed. This speed is generally 30 km/h. This is not the case when a signaling system exists since the aspect of the entrance signal is announced at the related distant signal (called approach signal). In this case the speed at station entrance is limited to 40 or 55 km/h depending on the kind of interlocking system.
In TMİ lines, the passing/overtaking operations are scheduled and shown on the timetables/traffic diagrams. If there is not any signaling system, trains have to stop at all scheduled passing/overtaking stations. If there is a signaling system, they may pass without stopping, because the required safety is provided by the interlocking system.
In 2004, TMİ system was in use on the following lines:
- Eskişehir to Alayunt; Afyon; Konya; Ulukışla and Yenice
- Alayunt to Kütahya; Balıkesir; Manisa; İzmir
- Manisa to Uşak and Afyon
- İzmir to Aydın; Goncalı and Denizli
- Irmak to Zonguldak
Manual Traffic Regulation is another train order system. This system is the same as TMI, with only one exception: the traffic regulation is done between the local operators and there is no line dispatcher. The local operators communicate with each other by means of telephone and even telegraph.