I will pluck up courage to make the first posting on this new conundrum...
Sir Edward Watkin always wanted to build a route from Manchester to Paris which would have required a tunnel under the English Channel. He served as director and chairman on the Manchester, Sheffield and Lincolnshire Railway and was the driving force behind the "London Extension" of that railway, which together became the Great Central Railway. He had a French connection as he held a seat on the board of the Chemin de Fer du Nord, which would have carried the projected railway from the French side of the tunnel to Paris. With regard to a Welsh mountain, I will hazard a guess that one of the locomotives that ran either on the Manchester, Sheffield and Lincolnshire Railway or the Great Central Railway carried a nameplate with that mountain on it.