Strausburg Rail Road #90 a 2-10-0 decapod, formerly of the Great Western Rail Road (Colorado, not the UK). As mentioned above, Strausburg Railroad is primarily a Heritage Railroad that runs excursions. It is also the oldest continuously operating railroad in the western hemisphere and has five operational steam locomitives. The SRR is still connected to the Norfolk southern mainline and still services industries along its line, which means you can occasionally see nearly century old steam engines hauling modern freight. Video related.
https://www.youtube.com/watch?v=Q5Myl6yG48o 