A lovely little treasure and piece of history. 
These are 1/4 1/2 & 3/4 mile markers from the direction signs (the type that would have a few arrow shaped signs on top of a pole, pointing in different directions). These originate from Dorset. 
They make a nice little thing to prop up on a shelf or make up the number of your platform (platform 9 3/4)
Measurements: 6.5 x 4.5cm
** please note 
They are in various stages of wear, but all readable.