I don't know what size, I'll measure the boiler tomorrow. Locomotive was dismantled because Alan wanted to rebuild the engine correctly instead of the farmer job. Chassis was sold a couple years ago to a collector in California who has since restored it to an original type trench engine if I understand correctly.Thanks for that insight. Is the boiler from a 19 or a 24 hp? Curious as to why the loco was dismantled? Looks to be a decent job from the pictures, wouldn't think some one would destroy such a kit. Myself am in need of a good boiler for our 24 Longfellow.