Navvy.

A contraction of navigator. One employed to make railways.

“Canals were thought of as lines of inland navigation and a tavern built by the side of a canal was called a ‘Navigation Inn.ʹ Hence it happened that the men employed in exoavating canals were called ‘navigators,ʹ shortened into navvies.”—Spencer: Principles of Sociology, vol. i. appendix C, p. 834.