这个词是什么意思？
Permanent roads having a line of rails fixed to ties and laid to gage, usually on a leveled or graded ballasted roadbed and providing a track for freight cars, passenger cars, and other rolling stock. Cars are designed to be drawn by locomotives or sometimes propelled by self-contained motors. (From Webster's 3d) The concept includes the organizational and administrative aspects of railroads as well.
中文名称索引；定义为 MeSH 英文原文，尚未逐条译审。MESH:D011890 · MeSH 2026。
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