Here are some detail pics of building the big Smokestack on the wood train.

To see this train in the tour of the shop: Visit to Brasstrains.com Headquarters in Ocala, Florida - YouTube

I built a long square vertical tower box that was imbedded deep into the sub frame of the tank framework for extra strength, that way the smokestack wouldn't snap off because its so top heavy yet so narrow at the connection point. I built a ring floating around at it's widest point with strips of pine like making a bongo drum. Each strip has an inner groove that I dado cut so thin support ribs can fan out and support the ring equidistant from the vertical box and keep it aligned and stable.

I made the 'collar' at the base of the square box tower (I'll show in another picture), then I connected long narrow slightly tapered strips of pine from the collar up to the ring. That becomes the underside angle flange of the smokestack. I pre built a circle ring with a flat bottom for the very top lip. Glued that to the top of the vertical box, then cut angled & mitered strips of pine that connected the wide ring to the circle on top.

Once everything was done I had to pad sand the angled wood strips and blend everything into one smooth compound curved surface. After all of that was the rivets, just using half round headed upholstery nails.

https://www.deviantart.com/rndmodels/art/Smokestack-Construction-Detail-876032447