agp - T3 [5 of 7]

T3 - the "Short" tunnel, note the curve & wall beyond.
That lump of concrete is reputed to be the mounting spigot for either a mortar [Blacker Bombard or similar] or machine gun, operated by the "Home Guard" and dating from WW2.
It made a convenient seat for a quick drink and biscuit break, whilst the members of the group collected themselves together.

As it was on the track alignment, it had to be demolished during the WHR's relaying. There are several others in the vicinity.