Love the wagons, both the IOA and the IEA, but (and I feel bad for making this 'but')...
The weights seem to be all off.
Both are listed as 37000 Kg tare mass, the IEA is 24,000 Kg according to network rail, the IOAs (as you've modelled, there are numerous versions in real life, but the IOAs modelled appear to be the re-bogied MLAs[1]) aren't so easy to track down, but a fair estimate would be around 22,000 Kg (the MLAs with older heavier bogies are rated for 23,100 Kg tare weight)
As for product weight, they both appear to have been intended for 90,000 Kg, although the IEA has a typo of 900,000 Kg.
But both those would be too high, a tare weight of 24,000 Kg would imply a maximum product mass of 75,000-78,000 Kg on the IEA. IOA should be theoretically rated for around the same, but in reality it's a smaller volume it can carry, so probably 60,000 is more realistic for it.
(Remember, the TF25 bogies are rated at 24.7-25.4 tonne per axle[2], and the IEA/IOA/TEA that use them are rated at 99-102 tonnes (depending on who you ask
Given that the IEA's look silly with their typo'ed maximum size, and filled to a realistic weight, and filled to the 900,000 Kg a '37 won't even budge pulling a couple of them, coupled together with tmz's logo comment, it might be worth doing an updated upload with the fixes.
[1] The I** series wagons are simply re-bogied existing designs that are also rated for International use (hence the I) by passing through the channel tunnel.
[2] The weight loading of a TF25/LTF25 is one of the few places the UK doesn't see a huge advantage, our previous bogies were generally rated for 25 tonne per axle too, other continental countries used lighter-loading bogies in the past though, so the TF25 has been a huge boost for them. The main advantage the UK sees is the decreased track wear from the double suspension.
Edit:
Experimentally 70,000 as queue size is still way too high, it results in a total wagon weight of 136 tonnes. Oddly trainz's version of maths seems to be a bit weird and non-linear, and it ends up that about 49,000-50,000 gives a reasonable load for the IEA starting from a 24,000 Kg tare weight (trainz does get THAT right at least). It's probably that ballast is defined as being fairly dense, but given that ballast is the most likely load for NR's wagons it makes sense to optimise for that load.
I'd personally put IOA at about 42,000 based on IEA being 50,000