Having started as a water boy, O'Brien was subcontracting for railroad work by the age of 18, then followed the new railways across the country during the early heyday of rapid railway expansion in Canada.We Lived a Life and Then Some: The Life, Death, and Life of a Mining Town. Between The Lines; 1996. . p. 45–. He arrived in Renfrew, Ontario as a teenager and, in 1879, he and two partners won the contract to build the Kingston and Pembroke Railway (K & P). While walking the future rail path between Sharbot Lake to the town of Renfrew, he happened to meet the Barry family, including his future first wife, Jane "Jenny" Barry, where her father, James, had built their home on the south shore of Calabogie Lake.Bytown "M.J. O'BRIEN", Bytown or Bust, May 8, 2012. Retrieved April 21, 2018. In 1891 he went bankrupt, after a disastrous contract for the Canada Atlantic Railway, then rebuilt his wealth through construction contracts.
