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 Post subject: C&O 1309 Low Pressure Cylinders
PostPosted: Wed Aug 21, 2019 4:03 pm 

Joined: Thu Jun 20, 2013 9:20 am
Posts: 8
Can anyone be of assistance in describing the function of the parts identified on the low pressure cylinders of C&O 1309 referenced in this photo?


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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Wed Aug 21, 2019 6:21 pm 

Joined: Thu Apr 14, 2005 9:34 pm
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Location: Copenhagen, Denmark
How many votes for drifting valves? Valves to let vapor/air move fore/aft in cylinders when throttle is closed?

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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Wed Aug 21, 2019 9:25 pm 

Joined: Wed Nov 23, 2016 7:05 pm
Posts: 247
I doubt drifting valves. More likely a wheel slip/power-reduction control since it's on the front engine. Appears to be able to vent both ends of the cylinder based on valve supply. Does the rear engine have it?

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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Wed Aug 21, 2019 10:08 pm 

Joined: Sun Aug 22, 2004 7:19 am
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Location: southeastern USA
Check the spiral pipe - it's a cyclonic evacuator.

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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Wed Aug 21, 2019 10:15 pm 

Joined: Tue Sep 14, 2004 7:52 am
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Location: Strasburg, PA
Drifting valves. There is a piston under each three stud head, with an attached valve poppet. When pressure in the steam chest rises, the pistons force the poppets against their seats at the ends of the rolled in tube, and the engine operates normally. When there is a lack of pressure, springs open the poppets, opening communication between both ends of the cylinder, keeping a vacuum from forming that might pull cinders into the moving parts.

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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Wed Aug 21, 2019 10:34 pm 

Joined: Fri Aug 20, 2010 8:25 pm
Posts: 402
I was going with "FLUX CAPACITOR", but I think Mr. Anderson has it correct.

A drifting valve setup to release vacuum conditions inside the cylinders/valves.

Not totally necessary to make a steam loco operate, but a refinement that reduces stress and overall wear and tear on the parts. And it keeps outside "grit' from being sucked into the "moving parts"..

When the loco is drifting with no steam supplied to the cylinders they become a sort of vacuum cleaner and will tend to "suck up" everything around them into the cylinders....

When everything around the loco is dust/dirt/grime/cinders it helps to avoid "Hoovering" them into the inside of the cylinder.


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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Wed Aug 21, 2019 11:13 pm 

Joined: Tue Jul 06, 2010 1:57 am
Posts: 210
NYCRRson wrote:
I was going with "FLUX CAPACITOR", but I think Mr. Anderson has it correct.

A drifting valve setup to release vacuum conditions inside the cylinders/valves.

Not totally necessary to make a steam loco operate, but a refinement that reduces stress and overall wear and tear on the parts. And it keeps outside "grit' from being sucked into the "moving parts"..

When the loco is drifting with no steam supplied to the cylinders they become a sort of vacuum cleaner and will tend to "suck up" everything around them into the cylinders....

When everything around the loco is dust/dirt/grime/cinders it helps to avoid "Hoovering" them into the inside of the cylinder.


Am I going crazy, or has to thread already happened once before? I feel like I've read this exact example of cylinders Hoovering things up a while ago.


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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Thu Aug 22, 2019 2:45 am 

Joined: Wed Nov 23, 2016 7:05 pm
Posts: 247
Kelly Anderson wrote:
Drifting valves. There is a piston under each three stud head, with an attached valve poppet. When pressure in the steam chest rises, the pistons force the poppets against their seats at the ends of the rolled in tube, and the engine operates normally. When there is a lack of pressure, springs open the poppets, opening communication between both ends of the cylinder, keeping a vacuum from forming that might pull cinders into the moving parts.

And the small pipe laying against the cylinder? Is that for make-up air then?

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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Thu Aug 22, 2019 7:33 am 

Joined: Fri Apr 26, 2013 5:56 pm
Posts: 234
Location: Ontario, Canada.
Does this loco have a compensating valve to allow live steam to the LP cylinders when starting a train, or is it always compounded? Thanks.


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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Thu Aug 22, 2019 10:44 am 

Joined: Thu May 24, 2012 1:37 pm
Posts: 1506
Quote:
"Does this loco have a compensating valve to allow live steam to the LP cylinders when starting a train, or is it always compounded?"


In the United States this is called an 'intercepting valve', and almost every true Mallet built here has one.

The 'better' designs took account of the difference in cylinder size and metered just enough live steam to the LP to equalize the starting power in the HP engine. That way the throttle could be inched out to the perceived limit of adhesion on the rear engine.

It is my opinion that the two little curved pipes at the top are the 'pressure reference' (to the exhaust passage in the steam chest) for the back side of the two pistons Kelly et al. have mentioned. (Suspect that would be admission steam pressure reference if the engine is not outside admission...

Note that these two pipes are ridiculously undersize to pass any actual mass flow for the kind of drifting bypass that would make a real difference on cylinders this size, so you know that's not their direct function. On this locomotive the 'bypass' is much more a 'vacuum breaking' effort than the kind of high-speed drifting that a system like Trofimov or Nicolai valves, or the Wagner setup on a locomotive like ATSF 2926, provides.

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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Thu Aug 22, 2019 2:39 pm 

Joined: Fri Mar 05, 2010 3:41 am
Posts: 3762
Location: Inwood, W.Va.
Great Western wrote:
Does this loco have a compensating valve to allow live steam to the LP cylinders when starting a train, or is it always compounded? Thanks.

Yes, the engine does have an intercepting valve for simple operation, and the evidence of it is what I recall is an exhaust pipe from the high pressure cylinders to the blast nozzle in the smokebox. This is the somewhat slim looking pipe curving up from the high pressure cylinders and below and outside the lagged (insulated) high pressure supply pipe under the running board. This is on the left side only.

Image

Before the management decided to be more restrictive with access to the shop, I got to look at a lot of the parts there, and among them was the blast nozzle. The best way to describe it was a bowl on a pedestal, with the hollow pedestal coming up through the bowl.

The pedestal was the pipe from the low pressure cylinders; the bowl surrounding it was the "nozzle" from the high pressure set when running in simple. A pipe connection came from the rear to "supply" this outside nozzle.

Lots of fascinating stuff with this locomotive!!


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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Thu Aug 22, 2019 4:13 pm 

Joined: Thu Apr 14, 2005 9:34 pm
Posts: 2528
Location: Copenhagen, Denmark
NYCRRson wrote:
I was going with "FLUX CAPACITOR", but I think Mr. Anderson has it correct.

A drifting valve setup to release vacuum conditions inside the cylinders/valves.

Not totally necessary to make a steam loco operate, but a refinement that reduces stress and overall wear and tear on the parts. And it keeps outside "grit' from being sucked into the "moving parts"..

When the loco is drifting with no steam supplied to the cylinders they become a sort of vacuum cleaner and will tend to "suck up" everything around them into the cylinders....

When everything around the loco is dust/dirt/grime/cinders it helps to avoid "Hoovering" them into the inside of the cylinder.


No, it is really necessary. Either you do this, or you have a cold air drifting valve on the valve chest. Without either one, not only do you suck in grit, but depending on the valve setting, you get really rough compression resistance when rolling.

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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Thu Aug 22, 2019 7:37 pm 

Joined: Thu May 24, 2012 1:37 pm
Posts: 1506
I suspect the "Hoovering" is less of a problem than the extreme duckwalking that the forward engine will produce with those huge cylinders on the end of their double hinge arrangement when there is inadequate or no compression 'cushioning'. The sorry little lead truck arrangement isn't even remotely qualified to compensate for that while drifting...

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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Thu Aug 22, 2019 7:59 pm 

Joined: Fri Nov 11, 2016 10:17 pm
Posts: 171
Overmod,

Can you explain the difference between the system you reference on the 2926 vs a traditional drifting valve?

Much appreciated!


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 Post subject: Re: C&O 1309 Low Pressure Cylinders
PostPosted: Thu Aug 22, 2019 8:30 pm 

Joined: Thu May 24, 2012 1:37 pm
Posts: 1506
Briefly, a conventional drifting valve just admits a little steam into the passages to 'break' any tendency for the cylinders to pull vacuum: a little under 15psia to make up for atmospheric pressure. This is often a valve instead of a 'throttle setting' as it's easier when running to just close the throttle up and then open something that gives free drifting. Pays to keep steam rather than air away from the cylinders and their lubricant, and of course atomized lube feed of cylinder oil still works correctly.

Problem is that the mass flow even at this pressure can be substantial over time, and it all 'counts' with regard to the water treatment system you're using. So systems were developed that would keep a charge of "vapor" from compression hot and shuttling between sides of the cylinder in alternation through special passages. Of course the Nicolai (and its stolen German version) and Trofimov valves do this fairly directly, by allowing the piston valve heads to slide on a center spindle worked by the valve gear. But there was also a variant made by the Wagner company in the 1930s, and this is what is put on 2926 and other examples of high-speed high-power ATSF locomotives including, I believe, the 5001 and up 2-10-4s.

I had hoped the 2926 group would have carefully disassembled and documented one or both these things and taken lavish pictures of the components but I can't find anything specific -- perhaps someone can direct me to a precise page of daily posting, or someone from the organization can provide a set of pictures somewhere on their site. (I don't do Facebook, but I can get my wife to download something if it's there) Of course 3751 also has these and they've even been cited in some popular Web
discussion of 'parts of a steam locomotive'

The Wagner is a type of spring-loaded bypass valve located in that 'third cylinder' visible on ATSF power so equipped. Here is a discussion from someone who researched this about half a decade ago:

Quote:
"The Wagner first appeared on the 3751 class of engines and was an integral part of the casting along with the cylinder and steam valve assembly. The Wagner is the very top “tube” like section above the conventional valve chest of the cylinder casting. This entire casting has special porting so the Wagner Bypass valve can close off the supply steam passage to the valve chest and open a passage between the exhaust ports on both ends of the steam cylinder effectively connecting the space on both sides of the piston together.

When the throttle is closed, a spring loaded piston valve in the Wagner moves over to connect the exhaust ports on both ends of the steam cylinder so the air [note that it's actually vapor] on both sides of the piston simply oscillates back and forth through the Wagner eliminating the need to supply steam to the steam cylinder to help cushion the piston while drifting. In addition, the Wagner closes off the steam supply ports leading to the valve chest. Basically, the steam cylinder is cutoff from the outside world. There was supposed to be enough of a restriction to the air flowing back and forth to each end of the cylinder through the ports that a small back pressure would be created and would sufficiently cushion the piston and brasses regardless of the speed. Slow speed, small backpressure. Faster speed, bigger backpressure or more cushioning.

When power is again applied by opening the throttle the steam travels to the Wagner Bypass valve where some of the steam is bled off to the exhaust nozzle but it begins to build up pressure against the piston in the Wagner, and after a predetermined pressure is reached it forces the piston against the spring and this reroutes the ports so the supply steam and the exhaust will follow conventional paths like a normal steam engine.

The theory was that there would be a substantial fuel savings because the fireman could set up a very light “spot fire” on long down grades that took a lot of time rather than having to fire for a drifting throttle working steam that was set according to the engineers technique. If you’re ever around an engine with a Wagner when they are starting to pull, you’ll hear a lot of steam making its way out of the stack as the Hoghead builds throttle slowly to get the Wagners to seat, and then suddenly there will be little if any exhaust and you’ll hear and see the steam blowing out of the cylinder cocks as he waits for the engine to react to the throttle."


The poster also had some comments on drifting and drifting arrangements you may find useful:

Quote:
"The Drifting Throttle is the standard where the Hoghead sets the throttle to feed the cylinders during slow and high speed drifts with enough steam to cushion the piston and brasses. Some of them used the backpressure gauge on the engine if it was equipped and most of the time they would just open the cylinder cocks and listen for the right amount of steam emitted for the speed they were drifting. On engines without mechanical lubricators it was a must to keep steam fed to the valve chest and cylinders in order to keep them lubed. This was standard practice on engines using hydrostatic lubricators.

I found a directive in one of the old Santa Fe brown books. According to the book, when you were drifting on long slow downgrades, they wanted the Johnson hooked up to minimize wear on the motion. However, the engineer was to drop the reverser down for a short distance once every ten miles or so in order to spread the lube over the entire face of the valve cylinder and force any oil that had accumulated there down into the steam cylinder. Those old boys had their thinking caps on.

The Drifting Valve was another smaller valve separate from the throttle valve and often fed from the steam turret in the cab with its output plumbed into the valve chest at a convenient location. I’ve seen some illustrations where it was preconfigured by the engineering department where it had small ports and the engineer simply turned it on or off as needed and lived with the flow provided by the fixed setting, supposedly. I’ve also read stories where the design engineers got it wrong according to the experiences of the engine crews and the Hogheads used a drifting throttle along with, or in place of, the drifting valve. They were not going to have their reputations clouded by handing off an engine that had the brasses burnt or pounded out of the rods to a relieving engineer.

I have combed the internet and a number of publications looking for information on these Wagner’s and any discussion on their proper use and details about their effectiveness that may be available . Talk about the Lost Ark of the Covenant. Scarce as a hen’s tooth.

Sad to say, the old fellow that I had as a mentor and actually worked the 3751 between L. A. and Needles, was from the old school when the 3751 class came along and simply ran the engine the same as he had run all the rest, drifting throttle. Wagner Bypass valves? “Didn’t use ‘em”.

I talked to an old roundhouse guy one time out of Albuquerque and it was his contention that they were to be used at any drifting speeds no matter what. I put that in the note book for future reference.

The only other info I could dig up was by inference from the book, Santa Fe’s Big Three, where there were exhaustive tests made on the 3400’s, 3751 class, and the 2900’s. They had a mind boggling amount of technical data, track charts, graphs, and tables that would suck your eyeballs out of your head after about five minutes but I battled my way through it a bite at a time and from what I can infer, they used the Wagner anytime they were drifting because it was a company mandated design intended to squeeze as much fuel economy out of the engines as possible.

When the Hogheads were on their own it’s anybody’s guess as to how many of them used it and how often, but when the dyno car was attached they were under the gun it was standard practice to use the Wagner.

The smaller external plumbing that you see is probably the drain piping from the Wagner, valve chest, and the steam cylinder. My understanding is the Santa Fe drained all these cavities individually to the cylinder cocks rather than allowing the condensation to work its way down to the steam cylinder and be expelled from there.”

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