Question for builders of Irish routes (IÉ and NIR)

[pfx]

In an effort to understand the building practices of those creating routes that are based in Ireland (north and south) I would like to know if builders working on standard gauge routes use UK standard gauge track or is there Irish gauge track that people use? I don't recall having seen an Irish gauge track or stock to run on it, on the DLS but I would like to confirm this is the case.

Thanks in advance.
PFX

 

[Vern]

The coupleof times I started, but unfortunately never finished, Irish routes I used the UK standard gauge bullhead track.