Steam & Excursion > ATSF 2926 Update - November 26, 2016, Valve work and more

After the last update that elicited multiple comments on valves, we have many pictures of additional valve work. More on that later. In the meantime, we have two new updates posted, new meeting minutes and a new newsletter. Whew! So lots to get to.

The updates (and meeting minutes) tell of the success of the preliminary unpressurized hydro and plans to make a fully pressurized one before having the FRA witness the defining one. Also valve reconditioning, electric work, brake work on the engine mover and a multitude of small jobs have occupied the volunteers this month. And going forward, the group will participate in several Christmas tours in cooperation with the city tourism folks.

http://nmslrhs.org/Status/status.php?week_no=201647   Work Session Status Week Ending 11/19/2016
http://nmslrhs.org/Status/status.php?week_no=201648   Work Session Status Week Ending 11/26/2016

Pictures and videos are from November 19 and include many of valve work including rehabillitation, cleaning and lapping; work on "Lurch" our car mover, and more hydro testing of superheater pairs.

http://nmslrhs.org/Photos/2016/11-19/index.html  Superheater bundle pressure testing, throttle valve lapping and steam chest valve refurbishment.

Information on becoming a sponsor for a letter or number for relettering the tender to the correct historical font can be found on our Facebook page:
https://www.facebook.com/NMSX2926/shop/?rt=19

More Society information, photos, videos and comments are also available on our Facebook home page:
https://www.facebook.com/NMSX2926/

Recent meeting minutes and our third quarter newsletter can be reached from links on our home page:
Our website and alternate:
http://nmslrhs.org/
http://2926.us

Luminaria Specials:
Visit ABQ put us on their website along with the ABQ Convention Center to have a Christmas Eve light tour from 6-10 PM. Luminarias are to be put on running boards and along rails.
ABQ Trolley and will do a Christmas tour event on December 10th and 11th from 5-9 PM.
If in the Albuquerque area, come visit and enjoy the lights.

Photos:
1. The relief valve is shown. This little one opens first to equalize the steam pressure on both sides of the throttle valves.
2. Our office staff. Madam Secretary Gail Kirby with Treasurer John Gibbons.
3. Our engine resting in her new home.
 

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Great. How are the kitty cats doing?

​Victor A. Baird
​http://www.erstwhilepublications.com

wabash2800 Wrote:
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> Great. How are the kitty cats doing?
>
> ​Victor A. Baird
> ​http://www.erstwhilepublications.com

Great! Well fed and they can get access to the neighboring building for shelter. I believe their water source is heated so it won't freeze with the early morning temperatures.

Picture 1....

The small poppet shown is most commonly called the pilot valve.
It admits steam into the lowest of three chambers: the balance chamber, which are cast cast into the superheater header.
The larger, main throttle poppets have a cylindrical base lobe just above the cam stirrups ( at the base of each poppet).   The 'balancing chamber' -and the balance lobes of the individual poppets DO equalize the pressures so that the throttle poppets be easily opened.

The actual 'steam controlling' poppets are flat disk-like poppet valves,
The covers over each valve have a cast 'guide-tube' on the under side, that keeps the poppets centered they raise to the extreme open position.  The poppets have a shaft extension on the top that fits into the guide tube, on each poppet cover.
The pilot valve lacks this guide shaft, since it is much smaller.

The manually operated camshaft has a series of cam lobes that open each valve in a specific sequence----- thus, the valves, once opened, stay open as the shaft is rotated.  So that the they are ALL  held open for maximum steam flow, and as the throttle lever is closed, the valves close in the reverse order.  The base-bar  of the stirrups allows the cams to be securely closed.

The 'balancing lobes' on each poppet have recesses machined into their circumference so that any steam that's is trapped in the balancing chamber, can escape towards the cylinders,  allowing the throttle assembly to securely closed.

W.

Thanks Wes. Below are pictures of the throttle rod and how it relates to the pilot/equalizing valve.

1. Throttle rod has lifting tabs at intervals.
2. Seen from the side these tabs lift one valve at a time as that rod is rotated.
3. The pilot/equalizing valve goes with the first tab.

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Very good pics  of the cams and shaft.
Thanks.

W.

In the 11/19 photo set, check out use of the special tools they made to do precise lapping of the throttle valve seats:

http://nmslrhs.org/Photos/2016/11-19/index.html