I have a photo of one of the station signs that is in the rail museum in York. Funny, I always thought it meant St Mary's Church (Llanfair) in the hollow (pwll) of the white hazel (gwyngyll) near (goger) the rapid whirlpool (y chwyrndrobwll) and the church of St Tysilio (llantysilio) by the red cave ([a]g ogo goch), even though I don't speak Welsh! Just had a feeling.
Truly amazing!And I had a funny feeling you might know where the original sign was . . . ;)