Track ballast
01
軌道バラスト, 鉄道バラスト
the layer of crushed stones or gravel placed under and around railway tracks to keep them in place and provide drainage
例
The workers spread new track ballast along the railway line to make the tracks more stable.
作業員は線路をより安定させるために、線路に沿って新しい道床を敷いた。
