one of the cross braces that support the rails on a railway track
同义词：tie, railroad tie, sleeper
crosstie详细解释
cross.tie n.（名词）A transverse beam or rod serving as a support, especially a beam that connects and supports the rails of a railroad.横木，枕木：一种起支撑作用的横向木杆，尤指连接和支承铁路轨道的枕木
