A lot of railroad buildings with slant roofs don’t have a chimney included. Some of the western style buildings don’t have outside chimneys, brick or stone. I’ve used the 54mm chimney from the Airfix Strong-Point set, cut out, and added to a bombed out building. I’ve checked the internet, and no one makes chimneys. You could be the first. A brick or stone chimney for roof tops, and a tapered 2 story brick or stone chimney for cabins. Thanks for reading this.