Abercynon Signal Box is a Great Western Railway type 27c design and was erected in its current location in 1932, previously having been at Birmingham Moor Street (1909) and Didcot Foxhall Junction (1915). Set on the station platform, it is a two storey structure of brick-to-floor construction under a hipped slated roof, with an external wooden access stairway at the north end. Containing an Individual Function Switch control panel of 1977, the box closed in 2008 whilst the panel and relay interlocking were transferred to the adjacent Abercynon Signalling Centre (nprn 417432) and was demolished in 2013.

Sources include: Peter Kay, Signalling Atlas and Signal Box Directory (Third Edition), Signalling Record Society, Wallasey, 2010; Network Rail, Signal Box Register (undated). For further information on the types and designs of signal boxes see: The Signalling Study Group, The Signal Box - A Pictorial History and Guide to Designs, OPC, 1986.

B.A.Malaws, RCAHMW, 11 November 2016.