VGN 2-10-10-2 - my 2014 challenge

[modelsof1900]

A first attempt for clarifying of sound of N&W Y6B - in original.

Before that, what I have written about steam sound of mallets is correctly, four chuffs at each older mallet that is working after the original mallet principle. But maybe there is an exception or more as one?

The N&W was this railroad with one of highest development in use of mallet engines. I have found an original N&W drawing with title "Arrg't. of Intercepting Valve and Separate Exhaust Valve, H.P. Cylinder, Loco. Class Y5,Y6,Y6a,Y6b" that maybe gives an explanation for existence of a separate exhaust pipe from HP-cylinder to exhaust nozzle. An item that not exist on normal mallets!
Maybe - and I would prefer to say maybe in moment - the Y6B sounds with eight chuffs while starting and slow running driven by additional HP-steam to LP-cylinders while exhaust steam from HP-cylinder will go to exhaust nozzle. So it will clarify the eight chuffs that we believe to hear in video.
A friend (a steam engine specialist) and I will try to study a few more documents for a more exact explanation.

Maybe I was wrong with my opinion to sound of modells of Y6B but not generally for all mallets. I hope that I can still give some further explanations.

ANOTHR EDIT: This site <!-- m --><a class="postlink" href="http://locodriver.co.uk/Vol05/Part09/02/index.html">http://locodriver.co.uk/Vol05/Part09/02/index.html</a><!-- m --> says "The N&W Mallets were provided with a simp[l]ing valve, enabling them to operate as four cylinder simple expansion locomotives. At starting, the exhaust from the high pressure (HP) cylinders was taken directly to the blastpipe, instead of to the low pressure (LP) cylinders as normal. This eliminated back pressure on the HP pistons at starting and meant an increase in tractive effort." Also, the Wikipedia entry on compounding says, "The eternal problem with compounds is starting: for all cylinders to take their weight, it is advisable to have some way of short-circuiting the HP cylinders and getting steam at a reduced pressure directly to the LP cylinder(s); hence many of the patented compound systems are associated with particular starting arrangements."
I have a feeling that simpling valves were common on Mallets.

jbw, your statement agrees with my opinion, I also still use a "maybe" - not for intercepting valve.
But I can not agree with your last sentence. All mallets had this simpling valves. The LP-cylinders need HP-steam for starting, yes.
But not all mallets are equipped with a second valve for a direct connection from the HP-cylinder exhaust steam to blastpipe! This an item that exist only on modern mallets. And that make the difference of original four chuffs for a standard mallet to eight chuffs of the Y6B.