Concrete floors in passenger cars?

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Posted by daveklepper on Tuesday, April 17, 2018 11:17 AM

Budd:  I think it was two layers of heavy-gauge stainless steel about two inches (OK wise-guy, 50mm) apart with some kind of honeycomb construction, not sure what material, between.

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Posted by Dr D on Tuesday, April 17, 2018 11:35 PM


Budd stainless steel car construction is recorded by White as follows,

"At the beginning of the lightweight age the revolution in car building was advanced by a entirely new material:  stainless steel.  As a miracle metal it outclassed aluminum on several counts.  It was incredably strong, yet ductile.  It did not rust, and its bright silver-grey appearance was most appealing.  It had been introduced in 1912 by Krupp, but manufacturers had thought it suitable for little more than cultlery and decorative novelties.  The metal, a combination of 18 percent chrome, 8 percent nickel, and low-carbon steel, seemed destined for only limited use.

Then the noble properties of stainless steel came to the attention of Philadelphia automotive parts manufacturer, Edward G. Budd.  Budd's specialty was auto body stampings, but earlier he had been in the railway supply field and was looking for an opportunity to reenter it...Budd soon realized that stainless steel had great potential for lightweight structures.  A surprisingly strong body could be fabricated from thin sheet metal...Budd also discovered that stainless steel was ductile: it could be pressed, drawn, and rolled without difficulty.  A deep cup equaled in length to its diameter could be formed with no metal failure  It was like working copper, yet this metal was nine times stronger than carbon steel and three times stronger than Cor-Ten.  Even subzero temperatures have little effect on its strength or ductility.  Cold-rolling resulted in a significant increase of tensile strength (up to 180,000 punds), but again without sacrificing its easy forming qualities.

Despite these positive findings, the matter of fabrication presented a serious difficulty.  In thin-wall construction, rivits or sheet-metal screws were not considered satisfactory because of the large number of fastenings necessary for an adequate bearing surface...Conventional gas or electric welding, even spot welding, created too much heat and ruined the metal, reducing it to little more than an inferior mild steel.  A special welding technique was needed.  The problem was given to Colonel Earl J. W. Ragsdale (1885-1946), Budd's chief engineer.  His assignment was to devise a method of quick, extremely high-temperature welding followed by instant cooling, meanwhile preventing the weld from coming to the surface of the parts joined.  By 1933 Ragsdale and his staff had perfected a method of electric, controlled-energy welding that is known today as the Shotweld process.  Precision control is essential; the current, applied for 1/60 to 10/60 second (at 2600 degrees), melts the metal of the two parts joined, allowing them to intermingle and bond.  The surrounding cold metal chills the weld.  In the welding of two 1/8" sheets, the diameter of the weld is about 1/4 inch...

Except for the side framing...All the structural members are made of thin gauge stainless steel, rolled or folded to shape and Shotwelded.  The outer sheathing is formed by fluted, snap-on stainless strips.  The center sills were 12- by 1 1/2- by 1/16-inch channels; the cross bearers measured 8 1/2 by 1 1/2 by 1/16 inches and were set at 27 inch intervals.  In place of the side-panel truss were large, upright channels (10 1/2 by 3 inches) formed of 1/16 inch stainless steel sheet.  (This method simplified fabrication, but it was apparently not stiff enough; in the next group of Santa fe cars Budd returned to the Pratt truss side frame.)  As was typical of the light weight cars, the roof served as part of the structure.  Like a bridge truss, it was the upper chord or compression member, and was meant to take one-third of the total bending moment of the body.  besides the carlines, no heavy supports were used other than two stringers running the full length of the car and attached to the collision posts at both ends.  The corragated roof sheeting itself was the main roof stiffener.  Being the largest unbroken surface area of the car, this great panel provided some strength for the body structure even though it was made of light-gauge sheet.  In the words of Colonel Ragsdale: 'It was not merely an umbrella to keep the weather out.  As an extra precaution against high-level telescoping, a collision bulkhead was formed by a 4-foot sheet welded to the carlines at each end of the roof.

The floor was corrugated stainless, but in place of concrete, a cork composition was laid in.  Linoleum was used for the top surface.  The underbody was insulated with 3-inch Dry-Zero airplane blanket.  As a gesture to earlier times, the interior was paneled in wood, but the paneling was only veneer mounted on presswood sheets... 

By the late 1930's it was clear that Budd had made a success of the stainless-steel passenger car.  Silver cars of its manufacture were rolling on the Reading, the Santa Fe, the New York Central and other major railroads.  By 1944 the company had produced nearly 500 cars.  The established car builders were understandably annoyed by the success of this upstart company.  Pullman's pique was fanned into outright hatred in 1937, when Budd began producing sleeping cars for Santa Fe; this was sacred territory reserved exclusively for Pullman.  Dark rumors were circulating deploring the unreliability of Shotwelding and Budd's general lack of experience, but they appear to have carried little weight outside Pullman's own sales office.  Pullman then decided to meet the competition head-on; it would produce its own version of the stainless-steel car.

Shotwelding, however, was a patented process held by Budd, and no satisfactory alternative method of fabrication had been devised.  Therefore Pullman decided to produce an ersatz stainless steel car, in which the structure and major fittings would be of Cor-Ten steel and only the side body panels and other bits of decorative trim would be stainless.  A side-panel truss helped support the body; and the outer corrugated side-panel covering was 'loose sheathed.'  In Pullman's lightweight steel cars the side pannel sheets were skin-stressed and thus served as part of the structure...After a few years, however, the cars exhibited a disasterous flaw.  To avoid unsightly fastenings, Pullman had copied Budd's snap on method of applying the stainless steel side pannel bands.  But there was no effective way to seal the cracks, so that water and cleaning compounds gradually seeped inside the cars lower body cavities. High pressure war washers only aggravated the situation.  The bodies rusted away out of sight, and it was not until major repairs were underway years later that the damage was discovered.

All stainless cars were not without critics.  High cost was the main objection; stainles steel was the most expensive material employed for railway car construction - 40 cents a pound even in the 1930's.  Budd's argument, however, was that the equipment would last for all time.  After thirteen years and 4.5 million miles the Denver Zephyr was overhauled in 1949 and showed no sign of deterioration in the stainless body or framing. In contrast significant decay could be expected in an ordinary lightweight car after such extended running...Overly durable cars only encouraged the railroads to make do with existing equipment.

Other critics challenged Budd's claim that stainless steel bodies were maintainance free.  It was true that painting was not required, though the Pennsylvania and the Norfolk and Western both insisted on Tuscan red exteriors.  However, keeping stainless cars bright was sometimes almost as troublesome and costly as cleaning painted cars.  More serious was the problem of major body repairs.  Few railroad shops were equipped to deal with stainless steel fabrication or Shotwelding, and after a smash up it was often necessary to ship the body back to Philadelphia..."

Despite these minor complaints, Budd made steady progress in obtaining orders and advancing the cause of the stainless steel car.  After World War II the company took over a war production plant in Red Lyon, Pennsylvania, for a new car shop.  Five assembly lines and 4,000 employees were soon at work, and by 1949 they had delivered more than 1,000 cars...The firm successfully revived the the rail car in 1949, calling it the RDC (Rail Diesel Car)...Budd decided to close its rail division in 1971.  Yet only two years later, Amtrak placed an order for more cars and the division was kept open."

- Dr. D    

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Posted by Piper106a on Wednesday, April 25, 2018 6:05 PM
My opinion, even eighty years after their first appearance the fluted side stainless steel Budd passenger cars, the styling is still attractive, a timeless classic look. I prefer their styling to much more modern smooth side Amtrak cars.
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Posted by 54light15 on Thursday, April 26, 2018 8:48 AM

And they're still rolling on Via's Canadian as everyone knows. They have an unlimited life expectancy, so I've heard. I knew about the concrete coach floors but paper wheels? I had no idea. 

Wouldn't it be nice if there was a heavyweight coach train that actually went somewhere today? They're what's on my N scale layout even though it's set in Germany in 1970. The DB did have coaches that looked like North American types and they still run on excursion trips. 

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Posted by daveklepper on Thursday, April 26, 2018 9:24 AM

Thanks for the correction concerning the floor construction.  And the rest of your detailed description.

Question:  To today's builders of stainless steel cars (including buses and mostly overseas, Japan, China, Spain, France) use the Shotweld process?  Have patents expired, or are royalties paid to a Budd-successor company?

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Posted by wjstix on Thursday, April 26, 2018 2:42 PM


As the OP here I always assumed that the floor was made out of some Urathene/Polymer composite that can withstand high traffic and yet be lightweight not unlike my Bowling Ball see 


Urethane bowling balls only go back to the early 1980's. I had one of the first ones, an AMF "Gray Angle"...with matching AMF gray bowling shoes by the way. Plastic bowling balls were introduced around 1960; before that they were all hard rubber (unless you go all the way back to 19th century wooden ones).  
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Posted by Deggesty on Sunday, April 29, 2018 9:40 PM





Several years ago, I first read of the existence of paper wheels--but saw no description of the construction. Thanj you, Dr. D, for your exposition.

Also, thank you for the details of "shot welding." That, also, was mentioned in Trains in the fifties--but there was no detail as to the process.

I did know of the problems that arose with the attempts, using an inferior process, to rival the beauty of Budd's cars.

I had never thought at all about the the nature of the floor in heavyweight cars; now I know.

I wonder: how long it will be before this thread is moved to its proper forum.


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