Others have commented here on the "duck-egg blue" colour of these yokes.
Having had a lifelong interest in liveries, I remember the first time I saw a spoil train "in the flesh", which must have been late '69 or so. The first thing I thought was, "What colour are they? What markings have they?"... As every wagon was so dirty that nothing at all could be discerned.... Dented sides as well, which as pointed out would be some challenge even for the very expert "weatherers" here....
See, I lived on the GNR side. Not this strange land of the NCC, where there were no proper goods trains, no "Enterprise" and thus no diesel locos, and what passed as goods was noisy railcars, no two alike, many of which were converted and even non-corridor steam stock, hauling brown vans or CIE vans to Derry! Quainter than fiction, this latter day 5'3" gauge Donegal-method operation....
Odd; odd indeed. But what wouldn't we give to see such a CDRJC-inspired collection of railcars, trailing wagons, today! Especially with filthy Jeeps rattling along a scenic shoreline with even filthier spoil wagons!
And those of us here who have been witness to more than a certain number of birthdays will reminisce; we thought it would last forever....
Just like ICRs today.
Hmmm.