The above diagram is the block diagram of our system.
Let us consider two Stations A having posts A1 and A2 and station B having posts B1 and B2 and two trains Train(1) and Train(2). Two stoppers have been provided just before the two stations. These stoppers are nothing but the LED part of optical sensor and these are in direct connection with the red LED of the post just after the stopper i.e. when the red LED of the post glows,the stopper becomes active. The train is provided with receiver part of the optical sensor and this receiver receives a clear signal before entering the station otherwise the train is automatically stopped by actuating its braking mechanism.
The two obstracles which are at the front and back side of the train are for Set and Reset of the posts respectively.These obstracles are attached on the train in such a way (one at front and another at the back) that they pass through the optical sensor and thereby set and reset the posts.
Green signal at post A1 :
Switch post A1à post A1_latch1_reset & post A1_latch2_reset
Green signal at post A2 :
Switch post A2à post A2_latch1_reset & post A2_latch2_reset
Green signal at post B1 :
Switch post B1à post B1_latch1_reset & post B1_latch2_reset
Green signal at post B2 :
Switch post B2à post B2_latch1_reset & post B2_latch2_reset
Note: Stopper A = red at post A1
Stopper B = red at post B1Situation for Train entering Station A The condition for Green light at post A1
§Cabin man has operated the starter switch post A1 on.
§Both Post 1(A) and Post 2(A) should remain Reset by the previous train.
§Stopper (A) of post1 is switch off Situation for train leaving Station A and entering Block AB The condition for Green light at post A2
§Cabin man has operated the starter switch post A2 on.
§Block AB is cleared by the Reset signal of the last train. Note:-
§The Situation for train entering Station B is similar to Station except Stopper (A) is replaced by Stopper (B).