Also, if there’s a problem with a train, the whole rail goes down. If there’s a problem with an airplane, the other planes have a whole lot of sky they can still use.
That’s not how rail works.
There absolutely are passing places where a train can hop onto the left track and then back again, or just a long stretch of an extra track going parallel to the main route where either the faulty train can sit and wait for repairs, or the working trains can jump around the faulty one.
Source: living in a country that actually has a working passenger railway system.





You don’t connect just those two cities, mate. You connect them as the main artery and then do split-offs to other areas. Or, even better, you weave the main railway between major cities East-to-West to connect them directly.