Sunday, April 1, 2018

Bonus Weekend Steam, Because Winter Just Won't Quit!

Thanks to Merle, I have a new ringtone on my phone today.  I have been listening to the Number 9 Shay at Old Threshers for quite some time, but today I have switched to this melodious locomotive.  Thank You, Merle!


3 comments:

JohnMXL said...

If you could address a curiosity for me, please...

I note in the videos of older steam locomotives that the exhaust from the stack seems to be relatively passive, presumablysmoke drawn from the firebox by natural convection and/or draft, such as a fireplace or woodstove would use for ventilation, whereas the newer steam locomotives seem to have forceful pulses timed to the cycle of the engine, and the exhaust plume lingers.

Do the newer engines vent waste steam thru the stack, and if so, is it done in a manner to aid in introducing air for combustion to the firebox, or to aid in drawing exhaust from the firebox, or is there some further extraction of the heat from the steam, or is it just cleaner or more convenient to send the water vapor up?

Thanks!

David aka True Blue Sam said...

Peter Cooper made the Tom Thumb in 1830, and it had a mechanical blower to create a draft for the fire. It was run by a belt from the axle. Nearly every other locomotive made has used an exhaust nozzle that directed the exhaust steam up the stack. The fireman had draft doors fore and aft at the lower end of the firebox to control the amount air that could come through the grates. If you go to steam shows you will find that every engine has its own sound. The combination of valve gear, steam cutoff in the valve gear, and boiler pressure all are factors in that. In the Twentieth Century advances were made in exhaust nozzle technology. https://en.wikipedia.org/wiki/Steam_locomotive_exhaust_system The appearance of the smoke also changes with fuel. Some burn wood, some burn coal, many of the newer engines burn oil. You also have shovel-fired boilers and stoker-fed boilers. Ride the Durango-Silverton and you will hear the engine work all the way from Durango as it goes north. As it returns from Silverton it is going downhill, so there is not much stack talk then. This is a big topic if you start looking at it critically!

JohnMXL said...

Thanks for the info and the link to lead me on a nice wiki-wander.

I thought I understood the basics of steam but I can see that there's a lot more to it than I realized!