Have a look at the above picture.
A blue board on the electric pole is showing 113/5.
Means it is 113 kms from certain point(probably counted from a main junction)
And the 5 denotes pole number in 113-114 km block. This is the fifth pole.
So how it can be used?
You can find out the speed of the train when you are in train using this numbering.
We are always eager to know the train speed when the train is in its full speed.
So open stopwatch in your phone. So when train crosses the pole 113/1 start the stopwatch. Stop it when it crosses 114/1.
So note down the seconds. Divide this from 3600(total seconds in an hour).
If your watch shows 36 seconds;
3600/36= 100 kms.
So your train is moving at 100 KMPH.
Next technique:
Look at the picture again.
The signal pole has with four splits.
One to the right and 3 to the left.
If only yellow is shown without any display in the split signals, then the train not taking any turn( means no track change).
If the right split signal with yellow is displayed then train is turning to the right.
In the above case train is turning to the left.
If left most split signal is displayed then the train is diverting to the third track from the main line.
How can this be used?
This can be used to guess the platform. In small stations train stops only for a minute. Its difficult to get down with your luggage. This helps you move your luggage quickly. To use this you need to have prior idea of the station. Google maps aerial view can also help you to count the tracks and see the expected platform.
EDIT: Many commented that they did not understand the second trick. Let me explain that with picture. This trick will not be helpful in very big stations like Secunderabad, Nizamudin etc. But most of the stations have less platforms and easy to guess. Thank you for the upvotes.
EDIT 2:
The maximum speed of the train is determined by the speed limit marked on each compartment. The above image shows that this bogie can go up to maximum speed of 110 KMPH.
So the maximum speed of the train will be the least of all the bogies. For Garibrath it is 130 and Rajdhani bogie it is 160.
Look at the image, a chain circled in green colour.
This chain is used to unlock the pressure which occurs when some one pull the chain to stop the train. The loco pilot or the guard has to walk up to the coach to unlock and allow train to move.
Edit 3:
I listed some techniques to get a confirmed rail ticket.