"Railroads" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus,
MeSH (Medical Subject Headings). Descriptors are arranged in a hierarchical structure,
which enables searching at various levels of specificity.
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.
Below are MeSH descriptors whose meaning is more general than "Railroads".
Below are MeSH descriptors whose meaning is more specific than "Railroads".
This graph shows the total number of publications written about "Railroads" by people in this website by year, and whether "Railroads" was a major or minor topic of these publications.
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