What if you took the principle of magnetic acceleration, created a bunch of acceleration gateways in space, and then shot space trains through it? Have catching gates on the opposite end for the deceleration part.

What's the maximum speed that magnetic acceleration can accelerate an object to in a vacuum before the object is travelling so fast that the magnetic effect can no longer impact upon it as it passes the gates?

I wanna build some fucking space trains. What can I read that's explored this?