[markpb]

I can't speak for Irish Rail but I did hire clamping companies in the past. A small site which won't provide much revenue will have to pay an annual fee to the clampers. Larger sites will get the service free of charge. In both cases, the clamping company keep all de-clamp fees. Irish rail has far more sites than I ever did so they may have come to a different commercial agreement.

AFAIK NCPS also run the park by text system used in Irish Rail car parks and may also provide and maintain any parking ticket machines. In that case, they're probably getting an annual fee and a per-ticket commission from Irish Rail.

Of topic but when you're on the other side of the fence and hiring clampers (for bad parking prevention, not revenue generation), it's an eye opener to see how inconsiderate and downright selfish an awful lot of people are when parking their cars. One week without clampers and people were parking across each other's doorways, on blind corners, blocking pedestrian entrances to car parks and, in one case, blocking a road so badly that DFB couldn't get past to attend to a fire.