What do W/L and C/Fa mean on a railway track

What do W/L and C/Fa mean on a railway track : While travelling and looking out of your window during the train journey, you must have often noticed that there are some votes near the railway track, which are written W/L and C/Fa. But what do W/L and C/Fa mean on a railway track ?

What is the full form of W/L

W or W/L is for whistle (also known as horn) indicator word. W means – Whistle, while 'W/L' means Whistle for level crossing. This means that where only W is written on the board, the driver of the train has to leave the horn.  

Where 'W/L' is written, the speed of the train has to be reduced by blowing the horn because there is an unmanned (a railway crossing that does not have a gate) railway crossing at a distance of 250 meters.

What is the full form of C/Fa

C/Fa is also stand for whistling sign. It is the Hindi version of 'W/L'. C/Fa means whistle ahead is the gate.  In hindi speaking areas Hindi bearing boards are set up.

What is the full form of W/B

Here W stands for whistle and B stands for bridge. If there is W/B is written then the train driver get indication that there is a bridge ahead.