K36-K37

The rear frame extensions on a K36 and a K37 are different since the firebox is designed differently. Other than that, it is basically the same running gear.

The smoke box is not part of the boiler. It attaches to the cylinder saddle. The boiler attaches to the smoke box. That is why the different size boilers do not seem to require a different cylinder saddle.

Looking at the photo of 485 at the bottom of the page, the so-called boiler front is actually the smoke box front and the first section of "boiler" that has the stack is actually the smoke box. The Smoke box and stack all together form a huge venturi to pull air out of the smokebox volume. The lower air pressure there by causes the highre air pressure in the firebox to be sucked through the flues.

The chuff we know of when the loco is working hard is not just the cylinder exhaust but the venturi accelerated air-steam-smoke-cinder mixture. The same acceleration principle is used by replacing the cylinder exhaust with boiler steam and the firebox air with a water line from the tender to get the cold low pressure water into the hot high pressure boiler.

FYI.

Doug vV