This line was built to transport materials and for earthworks in connection with the building of the Shannon Hydro-electric Power Station.
Approximately 8 miles of 900mm gauge line ran from Thomondgate area of Limerick city, across the Limerick to Ennis line on the level and carried on to O’Briensbridge. A short length of electric railway was also in use powered by 500V DC.
When project was nearing completion, a GSR branch was built to Ardnacrusha Power House resulting with some mixed gauge 900mm and 5ft 3in railway.
This line closed in 1930.