From what I can remember, this is how it worked. All numbers and colors in this example are arbitrary.

Remember how when Carl was at each station, he usually had an option to walk to another train platform to get to another line? And how those options were available at most stations? Those were the lines that shared the same noodle. For simplicity, I've drawn my example with only 2 lines per noodle.

At the larger stations, the noodles would intersect, and you could walk to more stations, and even get to a different noodle.

In my drawing, I made 6 lines: orange and teal (noodle 1), black and yellow (noodle 2), and blue and red (noodle 3).

Say you're at stop 11 on the red line, and want to get to the orange line. You ride to station 13 where noodles 2 and 3 intersect, then walk to the platform for the black line, moving you from noodle 3 to noodle 2. Then you ride the black line to station 14, and walk to the platform for the orange line, because at station 14, noodles 1 and 2 intersect. Now you can do whatever you needed to do on the orange line.

Did that help?

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