The original, brick-built, Chester & Holyhead Railway signal box at Penmaenmawr Station (nprn 34467) stood on the north side of the line. It was replaced in May 1887 by an early standard London & North Western Railway box directly opposite at the west end of the down platform, equipped with a LNWR Tumbler frame of 21 levers, numbered A and 1-20, and with block working by three-position combined instruments. The signal box was involved in the Penmaenmawr Collision of 27 August 1950 and was superceded shortly afterwards by a new box (nprn 421821) built at the eastern end of the station.
Sources include: An Historical Survey of Chester to Holyhead Railway Track Layouts and Illustrations, V.R.Anderson & G.K.Fox, Oxford Publishing Company, 1984. plate 202; The Penmaenmawr Collision 1950, A. Roberts, in The Signalling Record, No.36 (November 1992).
B.A.Malaws, RCAHMW, 02 February 2018.