Correct and you get the 2 tunnels separately.
Do you also get a Railyard skin as well??? I cannot remember.
You have the Dilapidated Railyard to start with, and at some point I got the skin for it in good condition, but can't remember how.
After you get all the stations and tunnels, the first batch of donuts is 10, I remember this because that was all I needed to get the Golden Goose Realty last year and missed, after that it is like you @camihendo1 said, 5 track pieces & 5 donuts on the fifth part every time.
And don't worry about not enough room:
1/ Get the donuts, store track pieces.
2/ When you have more land, you will have more track and more likely do something with it that you want.
I don't have ready access whenever I want and it depends on what I have to collect to get the blueprints.
If all 3 packs of blueprints want glass it can take a while.
But on a good week I have got 10 donuts before now, maybe close to 15, I can't remember, but then I do have Little Lisa's Recycling Plant as well which really does help.
And it stands to reason I don't rush any of it.