Other than establishing new rail corridors, GO Transit introduced the Bi-Level coaches in 1979, in order to increase the number of passengers carried per train. These unique rail cars were developed in partnership with Bombardier Transportation. In that same year, the former Bay Street GO concourse at Union Station was built to accommodate these additional passengers. GO Bus service also started on September 8, 1970, extending the original Lakeshore line to Hamilton and Oshawa, as well as providing service north to Newmarket and Barrie. It eventually became a full-fledged network in its own right after 1989, feeding rail service and serving communities beyond the reach of existing trains.