Question for the rivet counters

Do a search-engine search on "Stay bolts."  That should answer your question in more detail than I can.

Those aren't rivets.  Those are staybolts.  They hold the firebox in place and allow water to surround it.

Rivets are used to join the boiler sections together.

A steam locomotive is a marvel of a machine that is essentially pinned and bolted together.

Rusty

Thanks guys! Mystery solved!!

Most of what is pictured is of flexible staybolts with a ball and socket pictured on the outer shell of the fire box. The ball and socket end allows for some lateral movement. The inner connection is threaded/fixed and peened over to complete the installation. There are staybolts threaded/fixed through both shells of the fire box. This is a demonstration piece from Steamtown.  Fixed staybolts.  Note that staybolts were not solid, they were tubes with a hole completely through the bolt.  If it cracked or broke water would leak from either end of the assembly. They were replaced as part of frequent boiler maintenance.  Quick fix would see staybolts welded in place.

Did welded connections ever replace riveting in the later model steamers, as it now has everywhere else or were they always riveted until the last steamer was made? If welding was used does anyone know when they started using it in steamers instead of rivets?  I'm not a steam guy, just curious for trivial purposes.

rtr12 - later steamers - some of them - had welded boilers; the NYC Niagara did. Some

tenders (notably, not the Niagara's) were being welded, too. If you wonder why the

Lionel scale N&W 4-8-4 has such a smooth tender, that's why.

As with the staybolts, above, many of the "rivets" we see on our models were actually

nuts and bolts. Almost all those major "rivets" on the smokebox front of a steamer were actually bolts, else opening up the smokebox for service and repair would have been

pretty inefficient!

I'm not sure how many Modern steamers had welded boilers.

Anybody out there know the answer? Inquiring minds want to know. (And don't want

to do a lot of research, right now.)