How Do Train Depots Work?

Hi,

I’m having an issue with a new long train depot placed in the middle of a long rail line. The line worked fine until I placed the depot. Now when I click the magnifying glass to see where the issue is, it shows the rail right in front of the depot. I hate to bypass the depot, because it’s an important place to change out cars as needed for different cargo. But does the game treat them more as end terminals, that you have to send trains to using a rail junction instead? I love using rail in the game, and it’s very useful, but man is it tricky to get it to work right and mistakes can be so expensive. Any help would be appreciated; thank you!