A method and apparatus for lining a pre-existing pipe or passage having at least one curved section or bend along its length with a pipe assembly (10) is disclosed. An assembly is formed from a plurality of pipe sections (11), having axial ends (15,16) which are inclined at non-orthogonal angles (x) with respect to the longitudinal axis of the sections, and having interengagement means, placed end-to-end and engaged together. The pipe assembly is advanced into the passage or pre-existing pipe, pipe sections being vibrated such that the relevant pipe sections rotate relative to one another towards a relative orientation in which the axes of adjacent pipe sections within a curved section of pre-existing pipe or passage lie inclined at an angle to one another such that the pipe assembly can be advanced through the pre-existing pipe or passage.