This is a guide how to finish the puzzle "Locomotive in The Woods".
Stone + Stone = Fire + Stone + Stone (3 Times)
Fire + Stone = Metal (2 Times)
Human + Metal = Tools
Tools + Tree = Tools + Wood (3 Times)
Tools + Wood = Wheel
Wheel + Wood = Cart
Air + Water = Steam
Metal + Steam = Boiler
Fire + Wood = Ash + Coal
Boiler + Coal = Steam Engine
Cart + Steam Engine = Locomotive