In 1921, a royal commission into rail gauge was delivered, recommending gauge conversion of large areas of the country. It stated ""that the gauge of 4-ft. 8.5-in. be adopted as the standard for Australia; that no mechanical, third rail, or other device would meet the situation, and that uniformity could be secured by one means only, viz., by conversion of the gauges other than 4-ft. 8.5-in."" Following the royal commission, agreements were made for the standard gauge NSW North Coast line to be extended from Kyogle to South Brisbane (completed in 1930) and for the Trans-Australian Railway to be extended from Port Augusta to Port Pirie (completed 1937).