Boiler Dry Pipes Question

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Caribou Doug
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Joined: Wed Jun 15, 2011 4:24 pm

Boiler Dry Pipes Question

Post by Caribou Doug » Sun May 26, 2019 3:39 am


I am just completing the reconditioning of on older Allen 4-4-0 American that I acquired about a year ago. The locomotive sat for almost 5 years and was in need of a major disassembly and going over. Through the help of some friends in our local club (NEOLS) I have everything just about back together. The boiler on the locomotive was built by Ed Perry and seems to be in good shape. The locomotive had indications that it was coal fired at one time but when I acquired it there was a propane burner installed. In talking with some of the veteran builders in our club, they warned me to make sure the smoke box was sealed well so the engine would draft correctly. I followed their instructions to the best of my abilities and am pretty confident in the work I performed. One thing I had noticed late this evening when closing out the smoke box door and getting the propane burner put back in place is the dry pipes (2) were not sealed in the original build. I am hoping to fire the locomotive today and wondered if I should take any action to seal them up. One of the two has the blower supply line passing through and the second is unused leaving a 1/2" pipe and a good portion of the used one wide open from the back to front. Any guidance anyone can share would greatly be appreciated.


Caribou Doug
Posts: 92
Joined: Wed Jun 15, 2011 4:24 pm

Re: Boiler Dry Pipes Question

Post by Caribou Doug » Sun May 26, 2019 3:45 am

I also forgot to ask when firing with propane, is it necessary to draft the boiler with a vacuum until enough pressure is in the boiler to use the internal blower?

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Re: Boiler Dry Pipes Question

Post by Fred_V » Sun May 26, 2019 7:09 am

Those would be the hollow stays. The dry pipe is the steam pipe from the dome throttle valve to the smokebox. You can just cut wood plugs and tap them into the holes at the backhead as a temporary fix.

Exciting day for you to fire it for the first time. I'll be doing that with a friend on Monday on his build.
Fred V
Pensacola, Fl.

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Re: Boiler Dry Pipes Question

Post by cbrew » Sun May 26, 2019 7:27 am

I am assuming you are talking about the two hollow stays that run from the back to front,
yes you will want to seal them up. drawing air through those will do nothing good.
I used something as simple as cork plugs on the back head.
since i have moved to a smoke box throttle on my allen american, I machined up a brass bar that to support the rod on the engineers side and my steam chest gauge runs through the fireman's side
but depending what you are running through the hollow stays, you will need to fab to your specific needs.
and yes, you will need something to create draft, I just have a tap in my blower line fore shop air

Good luck!
If it is not live steam. its not worth it.

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Re: Boiler Dry Pipes Question

Post by NP317 » Sun May 26, 2019 10:14 am

Same hollow stays on my Ed Perry-built boiler for my Allen Ten Wheeler.
I machined simple brass cups that press onto the stay ends.
The left side supports the blower line into the smokebox.
The right side has a long stainless steel bolt through into the smokebox to hold the end caps onto the hollow stay.
These have worked perfectly for 15+ years. See pic below.

Like CBrew, I also have an external fitting to use shop air in the blower during fire-up.
pic below.
317 Cab 2small.jpg
#317 Air input.jpg

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