Discuss park gauge trains and large scale miniature railways having track gauges from 8" to 24" gauge and designed at scales of 2" to the foot or greater - whether modeled for personal use, or purpose built for amusement park operation or private railroading.
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Topics may include: antique park gauge train restoration, preservation, and history; building new grand scale equipment from scratch; large scale miniature railway construction, maintenance, and safe operation; fallen flags; track, gauge, and equipment standards; grand scale vendor offerings; and, compiling an on-line motive power roster.
Glenn Brooks wrote: ↑Wed Mar 23, 2022 1:07 am
To add to Greg’s question, does antique 100YO ASCE 12# rail have the same metallurgy issues you describe above.- needing post weld normalization?
Glenn,
Rail metallurgy has changed through the years, but steel rail has always been a high-carbon steel which is what causes the embrittlement when welding. It will need at least some post-weld normalization. Even if you don't apply more heat to the welded area at the very least you'll want to use thermal blankets or similar to slow down the rate of cooling as much as possible. Every little bit helps.
Some years back I helped pull up a backyard railroad there they welded channel iron to the 12lb rail for ties. After cutting off the channel iron the curved sections of rail were run through a rolling bender to straighten them. About half of the rails ended up snapping at one or more of the welded areas.
Welded rail can be perfectly fine in Frogs or Crossovers as the rail is being welded to a heavy steel plate that helps rigidly support it. Or even welding on Channel or Angle Iron for ties if the track is to be set into concrete where it's fully supported and can't flex.
Cheers,
Curtis
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Bill Shields wrote: ↑Wed Mar 23, 2022 1:51 pm
FWIW -> i have never seen a thermite rail welding operation that did any type of 'heat treating' after the thermite was finished...
Bill,
There is a pre-heating process and after the thermite is used there is a minimum amount of time the weld area is left encased in the thermite mold. Leaving the mold on to allow for the heat to dissipate slowly through the rails rather than immediately removing the mold and "air quenching" the welded area is the post-welding heat treatment.
Cheers,
Curtis
25+ Years of SolidWorks experience...now I feel old.
"You can lead a horse to water, but you can't make him drink."
"Winning an argument on the internet is like winning the Special Olympics."
www.facebook.com/HillcrestShops
Edit- if mig welding, wondering if a bucket of sand or desert dirt thrown over the weld would suffice to slow down the cooling process? Old time cast iron welders use a sand pit to slow down cooling of welded cast iron parts. ( plus a long post heating process )
Moderator - Grand Scale Forum
Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge
Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
Glenn, the standard slap stick method we use in the shop on such metals is to preheat them until the area near the weld will make the wood handle on a wire brush smoke a little, perform your welding, and let air cool. This should be done with a minimum ambient temp of 60*. If your welder is under powered, the pre heat will also help with that.
Dennis Larrick in Cincinnati has generously offered to work up CAD drawings of our future roundhouse. He got so enthused with the project that we now have elevation and planimetric and 3D views of the roundhouse, passenger station, and engine maintenance shed - all with a Spanish, southern motif.
Here’s a couple of screen shots of the structures we will be submitting for building permits.
The Union Station photo shows the motif we want to create for all of our structures - interpreting early day Southwest railroad develop as part of our small museum presentation.
A bit of brainstorming this week lead us to 3D print part of the roundhouse in S gauge and work toward creating an operating table top layout of our eventuall 15 ga freight yard, with 3D printed roundhouse and train depot. Great fun! More pics when we get it put together…
Glenn
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Last edited by rmac on Sun Jun 12, 2022 10:16 am, edited 1 time in total.
Moderator - Grand Scale Forum
Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge
Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....