 The Engineer William Stuart engaged in a dispute with the Committee over responsibility for the route selection, and was dismissed in October 1821.The contractor McIntosh was also dismissed amidst controversy over construction standards in June 1822, and Johnson Brothers (as successor to Johnson & Bryse) took over the work.Hopkins was now in charge as sole Engineer, he modified the specification for the later batch of rails; they were to be 3 ft 10 in (1,168 mm) long, with lapped joints at the sleeper blocks.