4 is a Kerr Stuart “Tattoo” 0-4-2ST built for the Corris Railway in 1921 and it worked on the Machynlleth-Aberllefenni line until it was withdrawn in 1948.
4 has made one visit to its original haunts but as the Corris Railway was not then passed for passenger trains it worked demonstration freight trains at the head of some surviving Corris waggons kindly provided by the Talyllyn.
The Corris Railway did not run any passenger trains during 2020 because of Covid-19 but plans are being produced to allow at least a basic service to operate in 2021 with time to clean and sterilise trains between trips.