steam dome question

stevedenver

stevedenver

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what is the difference between a steam dome and a throttle dome?

i had thought all steam domes had a throttle control within-that is, the control 'valve' of steam outlet from the boiler to the cylinders

apparently some loco had both-so what would a steam dome do if the loco had a throttle dome

i am aware that some locos had 2 steam domes to compensate for grades and the filling of the downhill dome-eg the Uintah mallet
 
Some domes just have a 'steam collector' pipe, the throttle valve itself is in fact in the smokebox, and is fastened to the front tubeplate and the superheater headers - I think all American 'modern' steam had these, sometimes known as 'front end throttles'. Some boilers didn';t have donmes at all - early LMS Black 5's for instance.

They were used in the UK, but only in the very latest engines (this is a bit of a generalisation, but accurate enough for this chat!!)

NHN
 
so why then would a loco have the two ?
 
For going up and down hill's I think Steve! always one avaiable for steam not water...............
 
Not really sure, Steve - I can only think of one British standard gauge loco that did (some members of the LSWR 700 class - known as 'camels'). The extra ones on US engines (and some brit narrow gauge) are sand domes of course, but I don't think that's what you mean.

Maybe to allow take off of auxilliary steam, for injectors etc, rather than the more normal turret in the cab? I'm really not sure at all. Anyone?

Neil
 
That is one heck of a beastie on only 750mm track - lovely. :D
 
<p>I think that's the LBSCRs' C-2Xs, similar looking to the 700s</p><p><a href="http://alan-lewis-chambers.fotopic.net/p18620449.html">http://alan-lewis-chambers.fotopic.net/p18620449.html</a></p><p> The second (front dome) was for Billintons top feed, 6 of the class were modified but the system was abandoned by 1930. THe domes remained in place and as the boilers were common to with the C3s, B2x, E5x and E6x classes they moved around locos as they were overhauled. </p><p>You can see in the picture (link) that the dome is still on the loco but the water feed is now in the usual side position.</p>
 
Brill picture link Wod. :D
 
Woderwick - 17/11/2009 6:26 PM

<p>I think that's the LBSCRs' C-2Xs, similar looking to the 700s</p><p><a href="http://alan-lewis-chambers.fotopic.net/p18620449.html">http://alan-lewis-chambers.fotopic.net/p18620449.html</a></p><p> The second (front dome) was for Billintons top feed, 6 of the class were modified but the system was abandoned by 1930. THe domes remained in place and as the boilers were common to with the C3s, B2x, E5x and E6x classes they moved around locos as they were overhauled. </p><p>You can see in the picture (link) that the dome is still on the loco but the water feed is now in the usual side position.</p>
Click to expand...

Ah, I stand corrected, thenks Rod - as a northern boy I'm not too hot on Suvvern stuff! Wrong class, wrong railway - but at least it was south of Watford Gap!! It was a fuzzy memory for sure. I plead age.
 
When I first saw this thread I was going to say C2X but Woderwick got there first. I always thought Drummond's 700 class were known as "Black Motors", at least in LSWR days - I just enjoyed the last of the class on local freights around Twickenham, during my schooldays in the 1960s.
 
fwiw-my query was in reference to an early Colorado Central engine-
 
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