There are a lot of strategies for handling this. One of which is, accelerate the pods on a separate, shorter (semi-circular?) track before merging into the mai

There are a lot of strategies for handling this. One of which is, accelerate the pods on a separate, shorter (semi-circular?) track before merging into the main "pod stream". Similarly, decelerate on a separate, shorter (semi-circular?) track. There was some prototype (or theory) of this discussed in a link on HN several months ago in which a Chinese train station accelerated (or decelerated, I forget) a car to match the speed of a passing train to append that car to the train as it went by. Just because you need to accelerate and decelerate doesn't mean you need to do it on the same shared track as the main line.