Author Topic: Eames Train Brakes - Official Work Thread  (Read 119129 times)

Jason M Lamontagne

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Re: Vacuum Brakes on the WW&F
« Reply #150 on: December 07, 2018, 09:54:26 AM »
When I get a minute this weekend I’ll post an update on the project.  Cold fingers now as we work on stove pipe installation in the shop.

Jason

Joe Fox

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Re: Vacuum Brakes on the WW&F
« Reply #151 on: December 08, 2018, 10:16:26 AM »
The vacuum brakes on the train will be different in that the vacuum will release the brakes. A loss in vacuum will result in applied brakes.

As such "angle cocks" will be needed to close off each end of the train. Check valves or flapper valves have proven insufficient and will not hold the vacuum. Or if they do, in short time the valve no longer functions as desired.

Hope this answers some of the questions floating around.

John Scott

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Re: Vacuum Brakes on the WW&F
« Reply #152 on: December 09, 2018, 12:30:15 AM »
Joe, angle cocks are not needed and are not used on continuous automatic vacuum brake systems because the hose at each end of a train is placed on a receptacle and held there by the vacuum. In between, the hoses are coupled together between cars.

It is the presence of cocks in air brake systems, necessary to retain air pressure, that introduces the danger of inadvertently closed cocks that would interrupt the continuity of the air brake system throughout a train. Introducing unnecessary cocks in a continuous vacuum brake system would introduce the same danger. Without continuity a train may have insufficient braking power to prevent a runaway.

I believe that there is not a direct precedent for the continuous automatic brake that is envisaged for the WW&F, however there is an admirable expressed intention to make it as Eames-like as possible. That means we need to be open to all relevant and applicable Eames precedents, otherwise it will not be worth the bother. For loco 9 the issue is particularly tricky, given its great historical significance and the wonderful work that has been carried out to get it to where it is, now.

Personally, I think the British-style hose couplings and acorn receptacles are much better than the Eames flap-type couplings and, accordingly, it would be reasonable to upgrade according to the British model. Hypothetically, the original WW&F management could easily have followed that path, based on their experience. Even so, it might be rather intriguing, given our museum status, to try to see whether the Eames connectors could be made to work!

The introduction of cocks has no reasonable precedent and it would be unwise.
« Last Edit: December 09, 2018, 03:35:21 AM by John Scott »

Joe Fox

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Re: Vacuum Brakes on the WW&F
« Reply #153 on: December 09, 2018, 01:12:18 AM »
My mistake. I thought coach 8 had angle cocks on it?

Jeff Schumaker

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Re: Vacuum Brakes on the WW&F
« Reply #154 on: December 09, 2018, 09:21:25 AM »
Is there a photo of an acorn receptacle that someone could post?

Jeff S.
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John Scott

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Re: Vacuum Brakes on the WW&F
« Reply #155 on: December 10, 2018, 08:37:53 AM »
I don't have a photograph handy, but here are some diagrams from a Google search.


John Scott

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Re: Vacuum Brakes on the WW&F
« Reply #156 on: December 10, 2018, 08:39:31 AM »
Dummy coupling.

Jeff Schumaker

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Re: Vacuum Brakes on the WW&F
« Reply #157 on: December 10, 2018, 09:52:53 AM »
Thanks for the image, John.

Jeff S.
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Jason M Lamontagne

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Re: Vacuum Brakes on the WW&F
« Reply #158 on: December 10, 2018, 07:59:33 PM »
Hello folks,

A quick review and update of our vacuum brake project.

Our design is, to the best of our ability, based on US Patent 241,333.  Specifically, lines 24-65, in the text of the patent, is the complete basis for car equipment.  As indicated beginning on line 32, a tenant of Eames’ design is avoidance of a packing gland on the double hemispheric shell type cylinders.  For our prototype, rather than custom produce the smaller rod seal diaphragms, we utilized a standard rubber bellows, which is housed in a tube and arranged so that vacuum is on the outside of the bellows, atmosphere on the inside.  We are utilizing the reservoir option as indicated beginning on line 63. 

For control apparatus on the loco, reference line 40, beginning at “automatically operating ejector,” utilizing a diaphragm balancing train pipe vacuum with a set of weights.  We took a liberty here and substituted the weights for a spring.  The user input (engineers control) is to set the compression on the spring via a set of ramped discs.  The mechanism either opens the train pipe to atmosphere or opens a pilot which snaps open a steam valve leading to the ejector.  We prototyped this, in rather ugly fashion, last year to prove viability.  We have now designed and are mid production on a version which is entirely self contained, 7” diameter and about 11” tall, which the ejector threads into directly. 

The locomotive control equipment will be completely independent of the locomotive brake system, thereby keeping (for example) loco 9’s historic braking system completely un-modified.  The train braking system on a locomotive will consist of a train pipe and a controller.  Additional plumbing includes a steam line off the boiler, ejector exhaust (with muffler), condensate traps, and shut off valves.

We have chosen this system because it allows fully automatic continuous braking within the historic context of the braking system on this railroad.  The car equipment is virtually identical to the straight brake found on the WW&F cars historically, requiring only the additional reservoir and some extra plumbing connections.  The locomotive equipment is simple and easily removable. 

We did prototype a much more complicated control system, involving a series of modern valves mounted under loco 9’s deck.  That system proved unwieldy to troubleshoot, and was a far greater compromise on historic integrity.  That equipment has all been removed; we’re all much more pleased with the current controller design.

Couplings:  loco 9 came from CT with its vacuum hoses which included the European style couplings, which came from the WW&F in 1937.  The hoses themselves were radiator hoses; we replaced them in kind (right from Wiscasset Napa).

With regard to John Scott’s question of angle cocks: we are using them so that we may isolate parts of the system for testing purposes.  Said testing includes the seals on the couplings, which we’ve yet to come to trust.  We also have yet to reproduce the stoppers as described.  As we’ve been heavily in testing mode, and have only one car equipped, it hasn’t been high on our priority list to refine that aspect of the design.  (IE we need a functional controller before the valves matter at all).  As to the danger induced by the presence of these valves- we have accepted such risk as equivalent to that found on a positive pressure system, and we may just need to leave it at a difference of opinion.

The project’s delay due to controller production coincided nicely with the bridge project taking all of our attention.  I do apologize if Mr. Scott, or anyone, has felt underinformed on this project.  The reality is our resources have been otherwise required, and we really wanted to have the new controller prototype in hardware stage before making a major announcement.  As it is, the controller production work has been proceeding back burner throughout this entire time.

We are also still refurbishing three B&SR vacuum cylinders; these will be for coach 3, which carried identical cylinders out of J&S (as evidenced by surviving mounting brackets).  This work is waiting for the shop to get some heat.  We have Jonathan St Mary who is essentially devoted to this project (pending heat), and several others who are supporting the project in various ways.  I’m providing project guidance, however for the most part I haven’t been on hardware work.  As winter brake work continues I’ll focus on 10.

Thanks very much for everyone’s interest.
Jason

Joe Fox

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Re: Vacuum Brakes on the WW&F
« Reply #159 on: December 10, 2018, 08:44:15 PM »
If the risk of the valves is sucking them closed during operation, maybe we could aquire some angle cocks or MU cocks that actually lock in position? The MU cocks found on diesels are spring loaded at the handle and lock in the open or close position and their position could be any position as needed.

Bill Baskerville

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Re: Vacuum Brakes on the WW&F
« Reply #160 on: December 10, 2018, 08:47:21 PM »
Jason,

Thanks for a very comprehensive and informative update. 

Bill
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John Kokas

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Re: Vacuum Brakes on the WW&F
« Reply #161 on: December 10, 2018, 08:55:18 PM »
Joe, I think you've hit on something there - might be a perfect substitute.  Hope the "Eames Gang" will give it a try.
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Brendan Barry

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Re: Vacuum Brakes on the WW&F
« Reply #162 on: December 10, 2018, 09:02:45 PM »
A picture of the brake controller valve pattern from Harold Downey and pictures of the cad model from Alan Downey.









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John Scott

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Re: Vacuum Brakes on the WW&F
« Reply #163 on: December 12, 2018, 05:53:22 AM »
I would like to express appreciation to those who have taken so much trouble to provide detailed information on the plans for continuous automatic vacuum braking. It is certainly understood that the tremendous input by all to The Bridge project and to going Down the Mountain has diverted attention from all sorts of other programs, including that of vacuum brakes. I am sure that many readers will be fascinated by the detail and impressed by the careful approach that has now been described.

In particular, I applaud the decisions to follow the Eames patent 241333 as closely as practicable and to keep the automatic brake separate from the Eames Driver Brake fitted to loco 9. It is gratifying to know that means have been found to make the car installations virtually identical to the straight vacuum (non-automatic) brake equipment that was originally fitted.

The Engineer’s Valve sounds interesting. I believe that there might be useful comment that could be made in respect of that, but I doubt whether this is really the place for so much detail. An aspect for consideration is the provision of a means for direct venting of the brake pipe in the event of an emergency.

It is difficult, indeed, to assist from afar without giving rise to perceptions of resentment for interference. One is not able to meet face to face with key players to form relationships of mutual respect and trust. It does need to be recognised that there is a distinction between considered professional advice and personal opinion!

As to end cocks, the diagram, below, shows a London Midland and Scottish Railway design that addresses all of the reservations that have been put forward in respect of vacuum brake hose couplings. Definitely, as world-wide experience has shown, there is no valid reason for end cocks to be fitted in a continuous automatic vacuum brake system and there are several important reasons against it. Where there is a will there is a way!

It is very interesting to know that loco 9 came with European vacuum hose couplings. That justifies the support for a degree of modernisation that I expressed in Reply #19, above.

If a Schematic Diagram of the continuous automatic vacuum brake system is developed, it would be most interesting to see it posted, here. Thought will be needed about safety issues such as the provision of a Conductor’s Valve in each car.

Again, thank you for a most welcome update on the vacuum brake project.


« Last Edit: December 12, 2018, 05:09:52 PM by John Scott »

Joe Fox

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Re: Vacuum Brakes on the WW&F
« Reply #164 on: March 18, 2019, 05:54:35 AM »
As we are doing all this restoration work, are we including provisions for the vacuum braking system?

Plans are to put vacuum brakes on the passenger cars currently then decide on the freight equipment. Personally I would like everything to have vacuum brakes. Especially when running photo freights and work trains down the mountain. With brakes working on every car a few weeks ago, I had a rather trerrifying experience on a ruling grade (not WW&F) of 1.8%. The grade is 1.8% for 2.1 miles, almost making it a FRA mountain grade but not quite. As an engineer let me tell you, you do not like to be in the seat and feel helpless.
« Last Edit: March 18, 2019, 02:35:44 PM by Joe Fox »