It was not unusual formerly for rainwater to be drained from a town street via a channel that ran between the pavement and the entrances to the houses. The stone across the channel was called a bridge-stone.
This is the north-country form of bridgemaster, the term for an officer within a borough who had responsible for raising the money needed to maintain a particular bridge: he may have shared the office with others.
In a rare use of this word an article was described as ‘broken’ when it was in its constituent parts and not damaged. It referred therefore to carts that were taken to pieces and stored under cover through the winter.