I like the art style you went for and I managed to beat the first 2 levels however I tried to do the last 2 as well however it felt overwhelming and I wasn't able to beat the last 2 levels as I couldn't keep track of everything as it was moving too quickly.
The sounds where fitting and I feel like the music matches the art style and theme.
For a game like this I would recommend adding a button to pause the movement of the trains so that the player could look over the level and maybe change some of the signals like maybe some kind of ready button to make the trains go instead of having them go right away.