Signs & Symbols of Indian Railway
Warning Indicators (Vulnerable Point Indicators)
A 'P' in a triangular or square board (black on yellow) advises the driver to be vigilant for track defects or obstructions on the track because of landslides, floods, etc. An 'E' in a similar board marks the end of the track section for which such advice applies (usually this is the rear of the matching 'P' board for trains approaching from the other side). A 'V' sign is often seen before entrances to tunnels or at other points in hilly...
more... terrain, etc., where there is a danger of landslides or rockfalls. It is also sometimes seen at the beginning of a bridge.