Generally, carriages carried one "snail", or, as in the Park Royals, none. This was the rule at Inchicore.
However there were oddities, both in lining and logos. Anything painted in Cork or Limerick could throw up surprises, for example a couple of old CBSCR bogie coaches on the West Cork system had two snails, dark green paint, but no lining at all. Cavan and Leitrim coaches had dark green paint on original stock, with only one light green band - above the windows, none below. The Inchicore rebuild of C & L coach No. 1 was, like most stock on the West Clare, turned out unlined and with no snail - nothing but the numeral.
The West Clare railcars never carried lining or snails, and both shades of green were used on different ones. Done old T & D stock turned up in both Ennis and Ballinamore, with no lining and either no snail or one.
On the main line, postal and all-parcels/brake vehicles often had no snail.
When new stock was silver, no snails were carried.