Artwork by someone called 'Curran' for CIE poster, around mid/late 50's when A Class were still in silver, full version here, another version has alternative wording for US market, offices in New York, Chicago, LA, etc:
http://www.irishrailwayana.com/CIEposA2L.jpg
Not of any actual location in particular, seems a trippy mish mash of somewhere on the South Eastern with a bit of the lakes of Killarney thrown in. Note cab that looks a bit early Sulzer-ish and interesting double brake hoses!