I was wondering whether somebody could advise me as to why some railways throw the fire (or at least part of the fire) out of the box during disposal rather than leaving the fire to die off in the box and then raking it through to the ashpan before the loco is next lit up? The reasoning I've always been given as to why the fire is left in (such as is done on the GCRN) is that it slows down the cooling process of the box and thus reduces the stresses of cooling on the inner firebox metals, so if this is true doesn't that mean the converse argument of removing the fire means the cooling process happens at a faster rate and thus increases the stresses on the metal? I can understand the advantage if the loco has a few hours layover after a sustained period in action (as might happen to a SVR loco during one of their big galas with night-time running) and one needs to remove clinker which has built up, but I can't see a reason to throw the whole thing out of the loco isn't needed back in traffic til the next morning, or next week. Of course, it may be that railways don't ever throw the entire fire out, and I am happy to be corrected on that matter. So, any wisdom?