noun
railway crossing gate; railroad crossing gate; level crossing gate
A barrier that lowers at a railway crossing to block vehicles and pedestrians when a train approaches.
踏切遮断機が下りている間は絶対に線路を渡らないでください。
Never cross the tracks while the crossing gate is down.
この踏切遮断機は列車が近づくと自動で下りる。
This railway crossing gate lowers automatically when a train approaches.
Compound of 踏切 (ふみきり, 'railway crossing') + 遮断機 (しゃだんき, 'barrier, gate').