Construction work on the section began in 1882 under the supervision of CPR engineer Harry Abbott, but went slowly as crews carved a route through the rugged La Cloche Mountains; by the end of 1882, all had been graded, but only of track had been laid. It was completed in 1884, but was considered below standard by the CPR, with bridges constructed from local timbers rather than the steel necessary to support heavy freight. This was intended to be the temporary western terminus of CPR line from Montreal, but construction on the eastern portion of the line north of Lake Nipissing had proceeded extremely slowly under engineer James Worthington, and only reached the Vermilion River by the end of 1883, in the process passing through a concentrated pocket of Jesuit missionary activity which would coalesce into the parish of Sainte-Anne-des-Pins. Worthington also placed a junction and construction camp at a place nearby, which he named Sudbury.