Mishaps at level crossings are the biggest killer in Indian railways. Accounting for 40% of train accidents and 66% of fatalities. India has more than 30,000 level-crossings at which vehicles can cross the railway tracks. Of these, more than 11,000 are unmanned crossings. This is where most of the accidents occur. Railway gate accidents are not unique to India. On average, each year around 400 people in the European union and over 300 in the United States are killed in level crossing accidents. Collisions can occur with vehicles as well as pedestrians. Pedestrian collisions are more likely to result in a fatality.
Automatic railway gate control systems have proved to be most suitable solution to such instances. Helping in automatically opening and closing the railway gate upon detecting arrival or departure of the train. This article aims to familiarize you with advantages of automatic railway gate control systems, their implementation in the real world and help you build your own project model.
- Automatic railway gate control systems reduce the time for which gate remains closed.
- This type of gates can be employed in an unmanned level crossing where the chances of accidents is higher and reliable operation is required.
- Automatic operation prevents errors due to manual operation.
- Lastly, no human resource is required. This makes its running cost very low compared to manned gates.
- To establish the entire network is quite costly task.
- Energy requirements are high.
- Involves complex network of connections and require skilled workforce to build it in a good manner
Real world implementation
The gates are required to be fully lowered 15 to 20 seconds before the train arrives and rise once the end of the train clears the island circuit. The time interval is controlled by a grade crossing predictor. It is an electronic device which is connected to the rails of a railroad track and activates the crossing’s warning devices (lights, bells, gates, etc.) at a consistent interval prior to the arrival of a train at a grade crossing.
All grade crossing predictors rely on the changes in the electrical characteristics of the rails that occur as a train approaches the point at which the predictor is connected to the rails. As the train approaches the feedpoint, the area enclosed by inductor diminishes. Thus reducing the inductance. For measuring the inductance, a constant-current alternating current source is connected to the rails. Now the resulting voltage is measured and by ohms law the voltage measured will be proportional to the impedance. The absolute magnitude of this voltage and its rate of change can then be used to compute the amount of time remaining before the train arrives at the crossing.
As soon as the computed time for train to reach the crossing reaches to programmed threshold value, the crossing’s warning devices are activated. The earliest grade crossing predictors used analog computers to perform this calculation. But modern equipment uses digital microprocessors.
Automatic railway gate using microcontroller
This project is an attempt to build a model of automatic railway gate using simple components such as microcontrolers, reflective type IR sensor, motor driver IC and a motor. It is based on the working of IR sensors (how do IR sensors work?). As in reflective type IR sensors no IR rays are detected by the receiver when there is no object(obstruction). Whereas when a object is present rays transmitted from IR transmitter are reflected back on IR receiver and hence detected.
Two reflective IR sensors are used for sensing the arrival or departure of train. They are placed at left and right side of the railway gate. Distance between the sensors depends on the length of the train. When the train arrives, sensors on the arriving side detects it and sends this information to the microcontroler. Microcntroler controls the motors and instructs them to close the gate. During the departure, sensors on the other side detects the train, followed by running of motors to open the gate.
Automatic railway gate operation using an Android device
This project is designed to control railway gate through an android application by the station master remotely. A smartphone or tablet with with an android-OS with a graphical user interface, based on touch screen operation is used to send the instructions to open and close the railway gate. Microcontroller once again acts as the brain of the project (learn arduino with us ). A wireless connection is established between the railway gate system(microcontroler) and remote(smartphone or tablet) using Bluetooth. Further, microcontroller controls the motors and is programmed to open and close the gates when the instructions are received. Gate can be remotely controlled by station master or driver himself. Android application used can be created according to the specific needs and can have features such as sending an acknowledgment about the status of the gate to the sender.
Indian railway is considered as the life line of the nation and carries 23 million passengers daily. It is also acknowledged as fourth largest railway network in the world by size. But recently it has been in news for all the wrong reasons such as increase in number of accidents. Its the need of the hour to modernize this system to make it more safe, swift and comfortable. Automating railway gates will be the significant step forward. This articles present the already available technology which can be put to work. Provided projects provides the fundamental concepts and principles of this system which can be further used to create new designs to target the limitations of current designs such as cost and energy needs.
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