In the section after you fall down the elevator shaft into the mushroom cave, there is a section in which you are supposed to run a motorized cart through the wall and retrieve some materials on the other side. In my first attempt, I sent the cart on its way while not standing on it, and it got embedded in the wooden wall without going through it, and then would not start up again, making it so that I could not progress.

Make sure you are standing on the motorized cart before you set it in motion to avoid this.