In August 1846, the Great Southern & Western Railway reached the county town of Carlow from Dublin. Two years later the line was extended to Kilkenny, and ultimately to Waterford. The station at Carlow retains the majority of its original GSWR buildings from the 1840s, including the main booking office, waiting shelter and covered footbridge, of which there are not many on Irish railways. The signal cabin was taken out of use with the resignalling of the line in 2003. Behind the station on the Down side is the former goods shed and yard, nowadays served by a single siding for loading ballast trains.