They fight lizardmen in the second one, but Thanquoul is accompanied by a bunch of Eshin rats, and no warlock engineers, so I don't think it is that one. In the first one, he's chilling with humans, and in the third, dwarves.
It might happen during the end times, but it is not in 'the rise of the horned rat'
So. If we figure out which skaven books feature Lustria (which is where they find the device, I believe) - besides the second Thanquoul book, we might find our source