Translation guide
The foundation layer of a road or railway, or the surface on which tracks are laid. In Japanese, different terms are used for roads vs. railways, and for the physical structure vs. the prepared surface.
The prepared base or foundation of a road, including the subgrade and pavement layers.
General term for the roadbed or base course of a road. Used in civil engineering and construction.
If the roadbed is weak, the road will deteriorate quickly.
Literally 'road foundation'. A more descriptive term, often used in technical contexts.
Construction of the road foundation has begun.
The foundation or base on which railway tracks are laid, including ballast and subgrade.
Standard term for the track bed or ballast bed in railways. Refers to the layer of ballast and the prepared surface beneath the tracks.
Replace the ballast of the track bed.
Also used for railway roadbed, but more commonly for roads. In railway contexts, it often refers to the subgrade below the ballast.
The surface of a road, sometimes loosely referred to as the roadbed in English.
Refers to the road surface itself, not the foundation. Use this when 'roadbed' is used loosely to mean the driving surface.
The road surface is frozen.
路盤 (roban) is a general civil engineering term for the base layer of roads and sometimes railways. 道床 (dōshō) is specific to railways and refers to the ballast bed and track foundation. Use 道床 when discussing railway track structure.
Do not translate 'roadbed' as 道路ベッド (dōro beddo) or similar. The natural terms are 路盤 or 道床 depending on context.
Work is underway to strengthen the railway roadbed.