Hey! Glad you "surfaced". I stumbled upon your nation a few times, and I think the countryside looks really good. However, Abella d'Or Prairie has sparked a lengthy debate on Verismilitude, a fundamental building block of OGF. I suggest you go there and participate, I put a link in your Forum post.
JADE Light Rail Network Map
Thanks, I'm glad you liked the map! It'll make it onto the wiki soon, now that I'm finishing up that metro area I'm going to sandbox some wiki pages for it in my user area. Would it sound strange to say that I created Tarkenton in order to be able to map out a detailed, sprawling light rail network, and I wanted the detailed, sprawling light rail network in order to try my hand at making a cool system map, or at least one that wasn't embarrassing?
After trying three or four other options, the tool I finally settled on was ConceptDraw. It has a learning curve, but all of the good vector graphics packages do. It is free (well, you can have as many 21-day trials as you have email accounts) which is a huge plus. And it even has a free Metro Map styles set. Check out https://www.conceptdraw.com/samples/maps-metro for examples of what those styles look like. The funny thing is that after messing with the styles I didn't use any of them but just went with one of my own. I'd be happy to share my JADE .cdz file with you to help get you started if you decide to play around with ConceptDraw.
(P.S. not the right place to say this, but I glanced at your work & really enjoyed what I saw. Just looking it over made me want to eat a bowl of clam chowder, so I'd say you're definitely hitting the vibe you're aiming for ;)