Incorporated in 1900 as the Kingscourt, Keady and Armagh Railway Company but the new company was unable to begin construction. Instead it reached agreement with the Great Northern Railway to build the 28-mile section between Castleblayney and Armagh, and abandoned the planned section between Castleblayney and Kingscourt. A new bill in 1902 reincorporated it as the Castleblayney, Keady and Armagh Railway Company.
A standard Irish gauge line between the towns, which was opened in 1909-10. The Great Northern Railway of Ireland subscribed £250,000 to the company, taking over in 1911.
Capital £500,000 in shares of £10.