THE IMPORTANCE OF THIS MODEL CANNOT BE OVERSTATED!
Others have described what they did, the fact they always seemed to be in the background doing unsung humdrum tasks (though there's nothing as humdrum as a modern railway with no goods at all, and nothing but the exact same railcar type, in the exact same formation, shuttling back and forth all day!)...
Bear in mind they were more numerous than the modern 201s, and almost as numerous as the 141s. MORE numerous than 181s, Hunslets, B101s or 121s. They did get about.
So, their history has been well commented upon, and to an extent which I hope will increase the rapidly growing interest in the "black'n'tan" and "grey'n'green" eras.
If we look at the more practical in these days of what they might be put to work at on a layout, we have a surprising number of options. The sheer variety of these is fodder for any modeller's imagination - anything from hauling a six-wheeled brake third, a couple of empty beet trucks and a tatty old 10 ton brake van on a remote branch line in 1960, to charging about the Dublin suburban area pushing or shoving clapped-out railcars in the 1980s. I encountered B209 at Attymon Junction on the Loughrea mixed two days before that line closed. The last two resident "G" class had been withdrawn from Loughrea earlier that year (1975) and had it remained open, only B201 / C types were to have been used. Even one "Supertrain" one, 232, did a stint there that summer.
You'd get them on weedsprays too.
They could be seen in both Crossley and GM form - pre- and post-re-engining - with goods trains, the Loughrea mixed (increasingly so before that line closed), ballast trains, and of course the NIR stuff. The "might have been" NIR ore traffic is another potential scenario.
The fact that they were less common on passenger workings in later years than, say, 141s, will be one of the reasons they were "ignored". The only cab run I ever had in one was on a ballast working from Clonsilla to North Wall.
So, they definitely deserve a pedestal by now.
Which I why I'm ordering some six of them; on my layout, had it existed in real life, pretty much all services would have been worked by these and 141s once steam ended.
This really is an IRM project which is WELL worth supporting.