Children's train bookmark

My 7-year-old son just started reading his first chapter book, so he wanted a nice new bookmark. I told him to design something and I would print one out for him (his drawing can be seen in the images above). I've tried to thicken the walls as much as I could without badly distorting the image, but it is still quite thin, so this needs to be printed slowly. I printed the flat bookmark part at normal speed and then printed the train itself at 30%. It worked pretty well for the most part, but my printer had a little trouble with the engineer, so bumping it down a little more might be ideal. At my son's request, the very top has a small ring that can be used to attach a ribbon or key ring.

I can't imagine there would be much interest in this because there are plenty of higher-quality options available, but I'm a proud father, so here we are.