Well, Sir, a lot of it has been published by the IRRS.
It's no secret, you only had to go to a Model Railway Exhibition at Bangor, Raheny or Blackrock to see (AND buy) the digitised books of Russell's NCC track diagrams and NCC Signalling diagrams. Still available - I'll provide you with the details!
As for NCR3 - that is MY FAULT. The manuscript is an arm's length from me. It hasn't been finished because when I asked (on a RPSI e-mail) about two years ago - less than twenty people stated an interest. Not the response you want when you're contemplating a £5-10,000 plus up front cost.
Russell covered the technical aspects of the railway at a fairly high level - as was typical in a David and Charles Railway History of the period when it was written. Since then, some of the material HAS been covered at very high level by experts in their respective fields.
However, I am exploring ways of getting the "book" out there and the "Signal Cabin" above has given me another idea .......
That said, it won't help you with this particular subject - the goods rolling stock chapter is just ten, double-spaced, pages and includes no lists of wagon numbers - merely how many of each type the railway had at various times.
I have been through Russell's material in the Archive and I don't remember seeing greater detail on wagon info - I may be wrong!
By the way, I agree with the Man from Seagoe that given two / three lifetimes a "volunteer" could go through Big Bob's diaries and make something of them - so in case there is reincarnation, maybe one of you would volunteer, assuming that The Almighty agrees! Thinking about it, there can't be reincarnation, as otherwise bob would have done it himself! They are fascinating, but like NCC wagon lists - of interest to maybe a hundred people on the planet.
Dinner's ready, I'll go before someone sends a hit squad to do away with me!
Leslie