hello curiously i wanted to try different fuels, so i bought a bag of the house coal smokey stuff, burned like hell very hot, very smokey blacked the glass but then cooked it off , i then bought some of the smokeless coal and it was a waste of time. i then bought some anthracite and again a waste of time , so i would say smokey coal was the hottest by far. i then got thinkin about railway sleepers and chucked a few pieces in. it burned very hot smokey but not half as smokey as the house coal. so i wander is it really that bad to be burning sleepers? i went out often to view the smoke out of the chimney and there was hardly any with the sleeper quite a bit more with the coal.. open to thoughts on this. i wont buy smokless coal again or the anthracite as its far more expensive and a lot less heat . be interesting to have some other thoughts on all this. if i can just say it is a modern stove that burns most of the smoke in the secondaries