I had a setback for a couple of days when I was modifying code to improve the function of the train station markers. I finally figured it out after taking a day-long break. I’ve got a lot more points of interest to add. Then finalize the new map tiles. And then publish. So now I’m looking to submit the revision to iTunes on Monday. 

With the map tiles, I’m making them so the CTA and Metra lines appear only at the highest zoom level. At other zoom levels they crowd the map. I’m choosing to show them as map tiles instead of as map overlays because the overlay is controlled by JavaScript and I believe it will run more slowly. The train station markers already slow down the app slightly (which is why they are turned off by default and you can toggle them).