Erin was one of two engines built by Hunslet in 1894 for the reopening of the Waterford and Wexford Railway. A company that had planned to build their line from Wexford to Waterford with a branch to the planned built Rosslare Harbour but due to a lack of money, only the Wexford to Kilrane(with Rosslare Harbour opening in 1895) line was built. The Fishguard and Rosslare Railway and Harbour Company intended to build Rosslare Harbour and develope the Railway. For this, they bought the two engines for the reopening where Erin was used to pull passenger services while the other engine Cambria, was used for the contruction and working of Rosslare Harbour pier. The service was marketed as th Rosslare and Wexford Railway as that reflected the route of the service more so than the WWR. Later that year the FRRHCo acquired the Wexford and Waterford Railway Company itself but continued to operate as the RWR. The FRRHCo was then jointly bought between the Great Southern and Western Railway(of Ireland) and the Great Western Railway(of Britain) in 1898 and Erin was absorbed by the GSWR.