I'm biased, because I like stuff related to public transit and infrastructure, but this is a great idea and a good interpretation of the theme! I like how the limitations and challenges placed on the player are difficult and interesting to work around/with, but don't feel inherently ridiculous or unreasonable. The dashed alternating colours when two lines share a road is a nice touch. I felt a little confused at points, but that was partially because I was looking away and missed parts of the tutorial. In addition, I found a few spelling errors here and there, and I noticed that the player has no bounds checking when they pan the camera around, so it's possible to go infinitely far away.
Good game! Best of luck in the jam.