road rail1
/ˈrəʊd ˌreɪl/noun
Usually in plural One of the bars or rails which form a railway or tramway. Now rare.
Origin
Mid 19th century; earliest use found in Journal of the Franklin Institute. From road + rail.
road-rail2
/ˈrəʊdˌreɪl/adjective
Of or relating to both a road and a railway; specifically (of a vehicle, typically an experimental one) that may be used on both roads and railways; (of a transport route, system, etc.) designed for or accommodating both road and railway.
Origin
1920s; earliest use found in Journal African Society. From road + rail.