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PRR T1 Trust posted update
http://www.rypn.org/forums/viewtopic.php?f=1&t=43986		 Page 4 of 4
Author:  CA1 [ Mon Dec 02, 2019 2:58 pm ]
Post subject:  Re: PRR T1 Trust posted update
Curious what the rough cost estimate is for the T1 frame/cylinders as a weldment ?

What about boiler rough cost estimate ?

As far as weight savings using weldments, wouldn't this potentially pose an issue with traction possibly necessitating the use of lead ballast etc to make sure the locomotive was properly weighted ?
Author:  Ron Travis [ Mon Dec 02, 2019 7:35 pm ]
Post subject:  Re: PRR T1 Trust posted update
SD70dude wrote:
Ron Travis wrote:
Bad Order wrote:
You guys aren't the only ones being steered away from castings, it seems like. This is the rear truck on some new EMD locomotive. All welded construction. Looks WAY less massive than it's cast counterparts, and I'd bet completely machine made... cut, assembled and welded. (the red arrows are the spring pockets)

To me, it's hard to imagine what it would take to make a huge, intricate castings like a loco frame. There are still some cast steel flatcars around my location. I look at them and think of what all went in to just making something as simple as that. It makes your head spin.


What specific locomotive is this truck in your photo from? What parts in the photo are fabricated rather than cast?


Looks like a HTCR-6 truck, as used under the SD70ACe-T4. Considering the grey colour I'm going to guess that is a Union Pacific locomotive.

I believe the truck frame is fabricated on these. Previous EMD truck designs, up to and including the common HTCR-4 used cast frames.

GE/WABTEC still uses cast truck frames, I believe they are made in South Africa or China.


Thanks for identifying the locomotive using this truck. I did find photos of the SD70ACe-T4 with that truck. It certainly is unusually stark looking, but I cannot tell if it is cast or fabricated. That straight, bar-like side frame suggests fabrication, but it seems to have big, round fillets between the frame walls and bottom flange like a casting would have.
Author:  Tom F [ Tue Dec 03, 2019 2:06 am ]
Post subject:  Re: PRR T1 Trust posted update
you would have to get up close, but if there is welds then it is fabricated.
Author:  Ron Travis [ Tue Dec 03, 2019 10:59 am ]
Post subject:  Re: PRR T1 Trust posted update
Actually, I don't see anything in the photo of that truck that appears to be fabricated. So I assume it is all cast steel.
Author:  Bad Order [ Tue Dec 03, 2019 8:09 pm ]
Post subject:  Re: PRR T1 Trust posted update
No need for further debate...the truck in question is 100% welded steel construction. The spring pockets may be either cast steel or forgings, but they're welded on to the assembly.

I noticed the engine was odd looking. Walked over to inspect it and take a picture. Just looking at it, the trucks looks undersized with the engine setting on it....like the wheels are smaller diameter. You can't get a feel for what I'm talking about in this closeup shot.

I think the engine number was UP 3020.
Author:  Ron Travis [ Thu Dec 05, 2019 9:14 am ]
Post subject:  Re: PRR T1 Trust posted update
This truck frame certainly appears to be fabricated because I can see welds all over it. Even the bottom flange of the sideframe is clearly a welded-on sheet or bar with several weld beads apparent in comprising the total fillet weld there. The spring pockets are clearly fabricated from tube and plate. This image can be enlarged to show lots of detail:

https://www.facebook.com/nsdash9/photos ... =3&theater

It is indeed a very unusual looking truck. I wonder if the design is dictated by the fabrication method of production, or if there is some other reason. I wonder if this signals an industry change from casting to fabrication or if the fabrication is just an option. It would be interesting to learn the pros and cons. Certainly, there has been an industry preference for casting truck assemblies up until now. Once in production, I suspect the time and cost for producing patterns is more than offset by the speed of the creation by pouring steel rather than cutting and welding it.
Author:  Overmod [ Thu Dec 05, 2019 11:41 pm ]
Post subject:  Re: PRR T1 Trust posted update
Quote:
"Finally welding large, thick, metal is difficult and slow. I once welded steel over 2 feet thick. I was running 425 amps with a 1/4 electrode. It took considerable preheat. Let me tell you the light coming off that arc was extremely intense even with the darkest lens. After a few hours you were spent. I also used powder welding to weld very thick walls on a dry dock when I worked in the shipyards. Extremely slow process and expensive."


Welding 2' steel with an electrode? What century was this?

The initial feasibility plan for 5550 involved a frame that is a combination of hydroformed plate and fairly large lost-foam castings, joined by laser keyhole welding (which easily accommodates heavy section with a very limited HAZ). Expectations were, and are, that use of the laser equipment and at least some of the training will be provided for PR or other value by people in the industry.

The principal reason for making one-piece engine beds even in the age of the PRR T1a (which involved precise weldments to heavy section and for which PRR had patent protection) was maintenance in heavy service, with even relatively small bracketing being 'cast in one piece' by the wizards at Granite City. In the modern age of autogenous welding there's little point in using excess metal of indeterminate strength and quality when a very precise section and setup jigs are relatively easy.
Author:  Tom F [ Fri Dec 06, 2019 12:36 am ]
Post subject:  Re: PRR T1 Trust posted update
Overmod wrote:
Quote:
"Finally welding large, thick, metal is difficult and slow. I once welded steel over 2 feet thick. I was running 425 amps with a 1/4 electrode. It took considerable preheat. Let me tell you the light coming off that arc was extremely intense even with the darkest lens. After a few hours you were spent. I also used powder welding to weld very thick walls on a dry dock when I worked in the shipyards. Extremely slow process and expensive."


Welding 2' steel with an electrode? What century was this?

The initial feasibility plan for 5550 involved a frame that is a combination of hydroformed plate and fairly large lost-foam castings, joined by laser keyhole welding (which easily accommodates heavy section with a very limited HAZ). Expectations were, and are, that use of the laser equipment and at least some of the training will be provided for PR or other value by people in the industry.

The principal reason for making one-piece engine beds even in the age of the PRR T1a (which involved precise weldments to heavy section and for which PRR had patent protection) was maintenance in heavy service, with even relatively small bracketing being 'cast in one piece' by the wizards at Granite City. In the modern age of autogenous welding there's little point in using excess metal of indeterminate strength and quality when a very precise section and setup jigs are relatively easy.


This century and it's called arc welding. I formally operated and maintained a Harris scrap metal sheer. This sheer exerted over 9,000 tons of force to cut scrap metal. The frame of the machine was metal several feet thick all around the sheer head. Needless to say welds occasionally broke which I re welded. https://www.youtube.com/watch?v=P20ZSa32TyA
Author:  Overmod [ Sat Dec 07, 2019 1:29 am ]
Post subject:  Re: PRR T1 Trust posted update
Quote:
"I formally operated and maintained a Harris scrap metal sheer. This sheer exerted over 9,000 tons of force to cut scrap metal. The frame of the machine was metal several feet thick all around the sheer head. Needless to say welds occasionally broke which I re welded."


OK, in that context I take it back, it made sense to do stick welding in that context. I thought we were talking about new fabrication where you could arrange the piece, jigged, both for easy downhand position and clean laser access and orientation in CA. (Or use something like electroslag if you wanted a general approximation of casting performance...) None of that would apply readily in your situation!

I'd agree that you earned more than you were paid, however much that might have been, to do that work!
Author:  Ron Travis [ Sat Dec 07, 2019 10:01 am ]
Post subject:  Re: PRR T1 Trust posted update
It seems that the point has been made here that for making large, complex parts such as engine beds and diesel locomotive power trucks, the steel casting process has long been obsolete, and has been replaced by steel fabrication. And yet we see diesel locomotive trucks being routinely cast right up to this moment.

But at this time, we also have this example of a fabricated power truck for a diesel locomotive: https://www.facebook.com/nsdash9/photos ... =3&theater

Is this fabricated truck the first example of a total conversion from steel casting of trucks over to fabrication? Or has this truck simply been fabricated for the purpose of testing the design before committing to making patterns for casting?
Author:  Overmod [ Sat Dec 07, 2019 3:46 pm ]
Post subject:  Re: PRR T1 Trust posted update
Quote:
"Is this fabricated truck the first example of a total conversion from steel casting of trucks over to fabrication? Or has this truck simply been fabricated for the purpose of testing the design before committing to making patterns for casting?"


In my opinion, it reflects that cost-effective full-penetration welding with full 'jigging' and preparation has made it less expensive, with better quality control, to provide these frames. In particular it reflects that HAZ-related damage is well under control both in design and as the built unit 'ages'. Added considerations of materials use, differential fabrication or structure, lower internal defects, or energy cost of fabrication may be elements of this, as would a desire to have 'common' or at least functionally interchangeable parts for a given class of power in service. But the 'bottom line' is almost surely economic.

Something else I think it reflects is the advance made in calculation, where much more precise determination of section and form, stress management, etc. can be made comparatively easily 'inside the computer' and then effectively and more and more rigorously tested there.

In a sense, this is opposite the 'engineering lesson' of the Scioto Bridge, where a large assembly of intederminate structure has less tendency to fall if critical members start to fail. We need to be careful not to get rid of the other point of a cast frame: the increased tolerance to cracking or other damage in producing prompt failure.

In the case of 5550's frame, the idea is to produce a very precise, strong and stiff structure, fully analogous in integrity and long-term stability to a cast bed, which benefits from some other considerations more suited to fabricated structures, such as the use of different alloys for different components or forged treatment of components to give effectively better-oriented strength for given dimensions. The frame is not designed to be 'lighter', but to use available material more directly, make any future maintenance easier and better, etc. In fact, with the lightening of the structure inherent in the welded boiler construction (vs. original) the frame may be made effectively heavier than original, with even greater increase in materials and fabrication integrity... not just added insurance mass of metal.

Note that most proposals for the frame do still involve a considerable amount of casting -- just that the individual castings can be made in lost-foam with less critical alignment and tolerances, and can be easily dressed or prepared for welding fabrication to give final, adjustable alignment via jig and precise measurement. This kind of 'hybrid' construction is familiar in heavy industry; I suspect someone like Rick Rowlands knows current practice better than I do, and others here as well.

I might carefully mention that what has been 'lost' in this country is not the ability to make large castings effectively, but the 'distinctive competence', in part through familiarity, in making cast-steel engine beds for steam power. I had thought these involved multiple timed pours in a highly (and probably, selectively) heated mold, through a careful and also preheated riser and gate system. As it turns out, GSC got to the point they could do this for Berk frames with only two timed simultaneous pours, which I wouldn't think could possibly work with the range of sections involved in one of the more complex unitized beds. There would be a learning curve in almost any foundry, and that learning curve would be in all probability excessive for a one-off design (and, of course, nonoptimal for any 'follow-on' duplex locomotive, which would almost of necessity have a better and larger firebox and grate arrangement, making much of the patternwork done for 5550 essentially worthless).

Incidentally, in my opinion at least, a diesel truck is not only a much smaller casting than any modern engine bed, but is far less dimensionally 'critical', as any good modern design doesn't have hard pedestal contact and uses individual-axle drive; in fact a good radial-steering truck may have no firm contact at the frame other than sliding weight transfer. This is in stark contrast to a typical eight-coupled or larger reciprocating steam locomotive, where the bed must remain both square and rigid to comparatively high tolerance over what may be a very long lifetime of hard shocks and thrusts, and the whole of both tractive effort and horizontal components of augment force has to be taken, longitudinally, through firm contact that remains trammed.
Author:  ted101 [ Sun Dec 08, 2019 4:32 pm ]
Post subject:  Re: PRR T1 Trust posted update
Looks like they just posted what the next phase is. Copied from facebook

"As you have seen what we have done building the boiler over last year, The T1 Trust is excited to launch our next phase in major fundraising. We are starting the push to complete the firebox portion of the boiler. With nearly everything complete in front of firebox we are ready to hit 2020 running. We need your help. The next phase will cost roughly $150,000. The good news is we have nearly half of that already pledged. We need your help for the last half to get this next phase of the boiler completed. This is the Bellpaire Firebox the Pennsy is well known for. Your donation will be applied to this famous PRR feature.

Watch your dollars turn into steel that will be generating the power for arguably the World's fastest steam locomotive. You can visit our website to make pledge/donation https://prrt1steamlocomotivetrust.org/station/index.php or right here on facebook. Thanks in advance for believing in us and please share with your friends! #yourdollarsatwork"



Image
Author:  PMC [ Sun Dec 08, 2019 7:53 pm ]
Post subject:  Re: PRR T1 Trust posted update
ted101 wrote:
"As you have seen what we have done building the boiler over last year, The T1 Trust is excited to launch our next phase in major fundraising. We are starting the push to complete the firebox portion of the boiler. ... The next phase will cost roughly $150,000. "


This isn't the eye-popping number I expected as I was reading this passage, though admittedly I am not the most knowledgeable about fireboxes. $150k can't be the total for a complete firebox, correct?
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