It never cease to amaze me how many times I miss routes that are available. I come to watch each of your episodes only after I have 5 stared a map, just so I can see how an expert does the job. On this map it did not occur to me that the Engineers could be connected directly to the back end of the customs gate. I was sending them right around and through the tunnel. Duh! 🙃 But there again, you did miss the opportunity to send home the 6 completed Engineers available from the very start for some quick easy money 😎
My different approach to this one was to concentrate on getting all of the tyres built first so they were out of the way either in the car factory or waiting to go to the home station. This means that once I started with the electricity that's basically all I had to focus on in the North and I did smash the building next to the fuel depot to get direct access from the tunnel. Also, if you are careful when placing the tracks from the North station, you can place a bridge feeding directly into the Car Factory (90 deg to the one feeding the tyres) for speeder transit in late game. But be careful. If your track is in the wrong position the construction of the bridge will destroy part of your track and kill your chance of 5 stars.
Did the layout of this level change at some point? Because when I was playing it, the customs had a different outgoing track piece, one that made conncetion via tunnel impossible EDIT: Not impossible. But you have to zoom all the way in for it to work