IMHO this is not about principles ... 21:47 Jan 8, 2011
... or anything. I'm in favour of good xlation practice and all that, but I suggest we keep this down to earth. I can see where you come from, Andrew, but to me, the main question is whether "rigid" transmits the idea of two opposing wheels on one conventional axle assembly, as opposed to the "Losrad" design mentioned elsewhere ... The decision whether to use this term or not is to be made according to the entire context, which is not available to us, so personally I will refrain from arguing too much about this one. But it just could work -- or not.
At any rate, using such a substitution is nothing out of the ordinary and per se doesn't infringe on anything. It just depends on the details. So let's discuss the latter -- though personally I wouldn't know what to add to the argument.
BTW I have no intention of turning this into an official answer... | 
The translation workplace 
