Pre-1925, all names were all n English forms only.
In formation of the GSR, a new standard was introduced, slightly off-white lettering on s black background. These were enamel signs (like the WLWR and MGWR often used), with the Irish version ingaeljc script uppermost, and the English version in Roman script below.
By the time CIE was formed in 1945, these had spread to most - but not all - stations. Many North Kerry stations, for example, retained pre-GSR English-only signs on wooden boards with cast iron letters screwed on. These were painted black, with white letters.
In the mid 1960s CIE introduced new signs with white backgrounds and black letters - the earlier standard colours reversed. These were plastic, and usually contained within varnished (later painted) wooden frames. While bilingual, Roman characters were used for both English and Irish versions.
A few old GSR enamels STILL exist - the footbridge sign at Carrick-on-Suir, for example.