I love 90% of this - the idea, the art style, the insane train physics, the economy and upgrading. What ruined it a little bit for me was the pace - It took me about 10 minutes to get the first upgrade and that barely helped. To keep any of the resources in the wagon, I found myself switching back and forth between the slowest speed and full stop, crawling along to the next sawmill trying to at least keep 4 wood in the cart. Not quite a "fury train" 😅. Maybe I was just doing something wrong.
Overall extremely cool concept, would love the difficulty and progression to be smoothed out a bit, then I could see myself really enjoying it!