Probably the single most important missing link for the 1950-85 (35 years!!) period missing now is the AEC railcar.
This is the only thing which spanned the steam era, the green’n’grey era, the black’n’tan era, and in the form of push-pulls the Supertrain era.
By the mid 1950s they monopolised many CIE main line services, if not most in some areas. They even made it to West Cork, Tramore, Omagh, Enniskillen and Newcastle. They ran on the Dublin to Belfast, Dublin to Cork lines, the entire MGWR, and Sligo to Limerick to Tralee and Waterford.
An AEC is as essential to a (main line) GNR setting as steam engines are. It is EVERY bit as essential to the CIE scene as green six-wheelers, “H” vans and J15s. It is as irreplaceable to this entire period as a DART is to a model railway of Connolly Station in 2018, or a 141 and 071 and Mk 2s to ANY 1980s layout.
Any ex-GN area UTA or NIR based layout of 1958-74 period needs them too.
For such s long period in railway history, comparatively few liveries are needed.
1. GNR dark blue & cream
2. CIE green - darker with simplified lining
3. CIE later green
4. CIE black’n’tan
5. UTA green with wasp stripes
6. GNR livery with UTA markings **
7. UTA lighter blue & cream - narrow cream band **
8. UTA lighter blue & cream - broader cream band
9. NIR maroon and light grey.
10. Black-ended black’n’tan for pushpull cars in CIE livery.
(** Versions 6, 7, & 8 were both extremely short lived and in all three cases only applied to a few examples, not (and nothing like) the whole fleet.)