Secured or fastened with crossties, or constructed with perpendicular supporting beams.
Past participle of 'crosstie' (noun), formed in 19th-century railroad and construction terminology. The adjective form emerged from the need to describe track that had been properly reinforced.
A properly crosstied railroad bed might look simple, but it represents an engineering calculation—each tie had to be spaced precisely to distribute a train's 200-ton weight evenly without buckling.
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