BASIC IDEA BEHIND PROJECT
There are so many different types of trains local, fast, super fast
passenger, good etc. and their so many multiple routes. Although
the time table is perfect it is not at all possible to maintain it. And that’s why the train accidents are becoming more and more usual.

The idea is whenever any engine observes a red signal on its track it
will start decreasing its speed gradually and stops automatically at
some distance from the signal pole. After then when it gets green
signal the driver can manually start the train and go on.

So now before the driver observes the red signal the engine itself
observes it and automatically starts decreasing speed and then stops.
The driver can feel relax in driving because he doesn’t have to take
care about red signal.
Demonstration Model
The train engine runs on 24V DC motor so that we can easily
vary its speed by varying applied voltage. The switching voltage
is applied in step of 18 V, 15 V, 12 V and 9v 9 V .

The 230 V AC is step-down to 24 V AC ,2 Ampere step
down transformer.

The IR sensor is placed at the top of the engine, senses the
signals transmitted by IR transmitter attached to signal pole.

Train track is straight and 20 ft long.
Components Description

1.Resistor:-
A linear resistor is a two-terminal, linear, passive electronic component that implements electrical resistance as a circuit element. The current through a resistor is in direct proportion to the voltage across the resistor's terminals.
2. Capacitor:-
A capacitor (formerly known as condenser) is a passive electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two conductors separated by a non-conductor.
3. Transistor:-
A transistor is a semiconductor device  used to amplify and switch electronic signals. It is composed of a semiconductor material with at least three terminals for connection to an external circuit.
REFERENCES
electronicsforyou.com
electroschematics.com
8051projects.info
electrofriends.com