This is why we have these guides to hold your hand, Geoff. It is literally as simple as building three of these loops (One outside each station and one in the middle) and you’re good to go. The benefits outweigh the issues by far, because of the game setup.
Unless you happen to be playing on Easy; where the economy is practically a sandbox in comparison, you’re going to need every cent early on. More rail also means more upkeep, which adds up as well.
You’re unlikely to be needing more than two trains on a single track at the start – Be it industry or passengers (One exception being a Coal/Ore/Goods line). Once my City to City Intercity rails begin attracting enough people to warrant another two trains, I just add them to the existing single track.
Now let’s say my needs change – I want to connect up more cities along this track or industries along the length. I’ll simply demolish the loops and convert it into a double track system with new loops for the “offspring” lines that link up to it. Put down one way signals at intervals and you’re good to go.