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 Post subject: Re: PRR T1 Trust posted update
PostPosted: Mon Dec 02, 2019 2:58 pm 

Joined: Fri Nov 11, 2016 10:17 pm
Posts: 47
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 ?


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 Post subject: Re: PRR T1 Trust posted update
PostPosted: Mon Dec 02, 2019 7:35 pm 

Joined: Sun May 15, 2005 2:22 pm
Posts: 1442
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.


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 Post subject: Re: PRR T1 Trust posted update
PostPosted: Tue Dec 03, 2019 2:06 am 

Joined: Mon Jul 02, 2018 8:04 pm
Posts: 163
you would have to get up close, but if there is welds then it is fabricated.


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 Post subject: Re: PRR T1 Trust posted update
PostPosted: Tue Dec 03, 2019 10:59 am 

Joined: Sun May 15, 2005 2:22 pm
Posts: 1442
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.


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 Post subject: Re: PRR T1 Trust posted update
PostPosted: Tue Dec 03, 2019 8:09 pm 

Joined: Sun Jun 23, 2013 1:16 pm
Posts: 105
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.


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 Post subject: Re: PRR T1 Trust posted update
PostPosted: Thu Dec 05, 2019 9:14 am 

Joined: Sun May 15, 2005 2:22 pm
Posts: 1442
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.


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 Post subject: Re: PRR T1 Trust posted update
PostPosted: Thu Dec 05, 2019 11:41 pm 

Joined: Thu May 24, 2012 1:37 pm
Posts: 1201
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.

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 Post subject: Re: PRR T1 Trust posted update
PostPosted: Fri Dec 06, 2019 12:36 am 

Joined: Mon Jul 02, 2018 8:04 pm
Posts: 163
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


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 Post subject: Re: PRR T1 Trust posted update
PostPosted: Sat Dec 07, 2019 1:29 am 

Joined: Thu May 24, 2012 1:37 pm
Posts: 1201
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!

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