I have been following up on this discussion and it strikes me that there is a misunderstanding in the idea behind this concept.
The idea is to make a sort of bubble in which the fabric of space can form in and not by the use of stationary tradelanes.
Why would you need to place tradelanes when you could take them with you on your ship? That is the idea.
So no, we do not thing tradelanes are engines. They are rather as you say what makes the ship move through it faster.
From these snippets of leaked to the public research done on the subject, it is already something scientists have been discussing that is possible.
We are not looking for anything drastically new such as turning as well. It is still going in a straight line forwards but 'taking the trade lanes with it' as a conceptual idea.
It is an idea founded on the principles of special relativity using trade lane technology as a means to the final product.