noun
: a block system in which a suitably inscribed staff is delivered to the engineer of a train or caught up by the engine while moving as authority giving the right of way to a designated station
noun
: a block system in which a suitably inscribed staff is delivered to the engineer of a train or caught up by the engine while moving as authority giving the right of way to a designated station
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012