Tom,
Interesting. It's gone from the CISX listing in my April 1944 ORER, so sometime between Jan. 1942 and then it disappeared into government service. Bear gave us the link to the only other picture on the web of it on Fallen Flags.
Hey, at least I guessed right on how long the depressed center platform was.
Now to figure out the disposition of the car.
Thanks for the tip on the Overland trucks. I'll look into that.
Mike Lehman
Urbana, IL
These may do the trick, #146....... http://bethlehemcarworks.com/Products/Kit_Bits/index.html I presume they're still available?
Bear,
Thanks, those may work, although something about them doesn't look quite right, maybe the wheelbase is too short? You gotta take what you can get with 6-wheel trucks, though.
OK, you were wrong (and me, too, on that), but you still made valuable and much appreciated contributions to this discussion.
I can't find that car anywhere in the 1948 O.R.E.R.; but it's right there on page 931 of the January, 1942 O.R.E.R.
Outside length 87'6"
Width @ eaves or top of sides or platform 9'8"
Extreme width 9'8"
Capacity 526100 lb.
Flat car, Depressed, steel, Note A: Car No. 500: height from rail to top of depressed platform 2 ft. 8-3/4 inch, to top of car body 6 ft. 9-1/2 inches; length of depressed center 18 ft.
Overland used to sell brass Buckeye tender trucks with either roller bearings or plain bearings. I have a set of the roller bearing ones, but you would obviously need the plain bearings. I've had mine for several years. Price on the box is $28/pr., but that price may be outdated (assuming the trucks are still available at all). Also, the trucks would need the brake cylinder mounted on the trucks, which means a mod.
Tom (the other Tom)
poppylOnce Livermore was created the AEC/DoD relationship changed. A lot of the AF's intel work was done with LLNL's Foreign Technology Division. Worked closely with Wright-Pat and very spooky groups within and without the government. That's about all that can be said. Poppyl
Well, they finally put Teller where he could do all the cool stuff he was always promising at LLNL where no one would be "holding him back. "They didn't start off too well, I forget how many fizzles before a good one, then Teller ended up building low yield weapons, too, just like Oppenheimer wanted to do and did, fortunately, after the high yield ones proved impractical. And that "clean" weapon thing never went anywhere despite all his and Louis Strauss's promises.
Yeah, there's a LOT more to that story
LLNL was well situated to work with what became AFTAC's Technical Operations Directorate at McClellan though. AFOAT-1's main fallout sample analysis labs were there, as that provided fastest access to the Pacific and the synoptic weather routes that were the primary surveillance method for fallout. This also situated them well when atmospheric testing was still going on. That's my main interest in the AEC, because each test series for the weapons designers also provided the opportunity for intel R&D work.
Dad worked at Wright-Pat doing development work there after coming back from Saudi Arabia, where he did whole air sampling for the krypton-85 monitoring program. He worked on the team that took what he called "a room-sized apparatus" that required a team to operate and converted it into something about the size of a fridge that could be run unattended most of the time. We then went to Panama for a spell around 1960, then he went to OCS and got into training for most of the 60s. Then off to USAFE at Wiesbaden for awhile then back to Chanute here where he managed more training. I suspect this was connected in various ways, due to certain facts I now know, but he doesn't say much even after they gave the vets dispensation to at least acknowledge their service publicly at the 50th annivessary of AFTAC in 1997. Gets to be a habit.
BTW, there were just two year's worth of unit histories available declassified for AFOAT-1/AFTAC, previously available through the National Security Archive, but after a lot of patient MDRing as part of my project, all from 1947 through 1964 are now available after I got the last one a year or so ago. There are a relative few redactions, but most of it is there. I don't know in what form these might generally be available yet, but getting them webpublished is one of my post-grad projects so all the oldtimers can consult them.
mlehmanI am considering building a model at some point. The trickiest part will be the trucks, but at least I have a good idea what's needed.
These may do the trick, #146.......
http://bethlehemcarworks.com/Products/Kit_Bits/index.html
I presume they're still available?
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."
"Seek and ye shall find.."
I've been cheeky and also linked this photo that you've referenced else where Tom.
http://www.rr-fallenflags.org/misc-frt/cisx500alb.jpg
I see that I was wrong in my assumption that the car had been modified, but hey, the truth will out. From me, thanks Tom.
Now, whats Mikes next conundrum?
Cheers, the Bear.
OK, sounds like we have a winner!
It certainly looks the part and has all the right stuff in the right places after a quick once over. May I ask what else you know about the circumstances under which it brought JUMBO to New Mexico? Did the government keep her after TRINITY?
The 1st pic on your webpage does look a lot like 1941 (or maybe 1942) to me. That load would hardly strain it much. Maybe an open house at C-IS? I kind of assume that she was busy with the war until someone from the Manhattan Engineer District called an inquired about it, maybe in 1943 or even early in 1944?
That's a great ad, too.
Anyway, it would be a cool addition to your webpage to have some reference to its history. I don't think we're yet sure of a final disposition or perhaps you know?
I am considering building a model at some point. The trickiest part will be the trucks, but at least I have a good idea what's needed.
The car that was used to carry this vessel was the CISX 500. It was built for Carnegie - Illinois Steel, by Greenville Steel. There are a couple of photos on my website. http://southern.railfan.net/flat/cars/cisx/cisx500.html
Tom
mlehman I guess I was thinking that the guns might work, but the turret was too wide for RR transport. I used to have good references on Navy stuff, but lost them in a fire some years back and didn't replace them, so I'm going by memory on sizes here, which isn't always really reliable these days. poppyl I believe that the 280 mm gun did get prototyped but ended there. Long Tom was the largest nuclear rail gun that actually fired a live nuclear round. Yeah, don't know about the 280mm in Navy service. I suspect you're thinking of the 16" AFAP, which AFAIK, was the only Navy AFAP. It actually started off as a Army round, intended for the Coast Artillery, but it was disbanded. I had a great-uncle in the Coast Artillery. I always thought that was a pretty safe assignment to spend a war, but I digress... In fact, the Navy joined the AF in opposing the 280mm, but they did want the 16" AFAP. The Army then redesigned the components to fit the Navy 16" shell. Ironically, the 280mm AFAP physics package was exactly the same as the Mark 8 Navy bomb. The weird politics of weapons design, I guess. BTW, I use Chuck Hansen's Swords of Armageddon compilation for most of my quick reference, specific cites re weapons and he's pretty reliable, although the set isn't cheap (~$300). It was cheaper than his original Secret History of US Nuclear Weapons when it came. Before the SoA CD set came out, copies of it started at $900 in the used market. Now they start at a more reasonabkle $150....I'mreally glad I bought mine when first published for something like $29.95. Yeah, the early AEC has some interest, but my primary research is the one thing that was more secret than our bombs -- intelligence about THEIR bombs. Long story, but the Air Force moved to compartmentalize the project (AFOAT-1, later AFTAC) off from the AEC, in part because of their desire to get Robert Oppenheimer cashiered, which they eventually accomplished. In the end, Oppenhimer's ideas (use small tactical weapons) saved the day when it turned out really big thermonuclear weapons were not such a good idea, which Dr. Oppenheimer tried to explain might have a substantial problem with fallout...so there is a connection, but the AEC was often in the dark about what the Air Force was up to. Consequently not much there. Been to Nara several times, plus Ike and JFK. There's only so much they can help, but I pretty much got what I need (between recent decalssifications and some things I managed to get through MDRs), if I can just get the darn thing wrapped up.
I guess I was thinking that the guns might work, but the turret was too wide for RR transport. I used to have good references on Navy stuff, but lost them in a fire some years back and didn't replace them, so I'm going by memory on sizes here, which isn't always really reliable these days.
poppyl I believe that the 280 mm gun did get prototyped but ended there. Long Tom was the largest nuclear rail gun that actually fired a live nuclear round.
Yeah, don't know about the 280mm in Navy service. I suspect you're thinking of the 16" AFAP, which AFAIK, was the only Navy AFAP. It actually started off as a Army round, intended for the Coast Artillery, but it was disbanded. I had a great-uncle in the Coast Artillery. I always thought that was a pretty safe assignment to spend a war, but I digress...
In fact, the Navy joined the AF in opposing the 280mm, but they did want the 16" AFAP. The Army then redesigned the components to fit the Navy 16" shell. Ironically, the 280mm AFAP physics package was exactly the same as the Mark 8 Navy bomb. The weird politics of weapons design, I guess.
BTW, I use Chuck Hansen's Swords of Armageddon compilation for most of my quick reference, specific cites re weapons and he's pretty reliable, although the set isn't cheap (~$300). It was cheaper than his original Secret History of US Nuclear Weapons when it came. Before the SoA CD set came out, copies of it started at $900 in the used market. Now they start at a more reasonabkle $150....I'mreally glad I bought mine when first published for something like $29.95.
Yeah, the early AEC has some interest, but my primary research is the one thing that was more secret than our bombs -- intelligence about THEIR bombs. Long story, but the Air Force moved to compartmentalize the project (AFOAT-1, later AFTAC) off from the AEC, in part because of their desire to get Robert Oppenheimer cashiered, which they eventually accomplished. In the end, Oppenhimer's ideas (use small tactical weapons) saved the day when it turned out really big thermonuclear weapons were not such a good idea, which Dr. Oppenheimer tried to explain might have a substantial problem with fallout...so there is a connection, but the AEC was often in the dark about what the Air Force was up to. Consequently not much there. Been to Nara several times, plus Ike and JFK. There's only so much they can help, but I pretty much got what I need (between recent decalssifications and some things I managed to get through MDRs), if I can just get the darn thing wrapped up.
Sixteen inch shell had a very short stockpile life -- logistics train was a bear and missile based options developed shortly thereafter supplanted it.
Once Livermore was created the AEC/DoD relationship changed. A lot of the AF's intel work was done with LLNL's Foreign Technology Division. Worked closely with Wright-Pat and very spooky groups within and without the government. That's about all that can be said.
Poppyl
ACY Maybe I'm misunderstanding something. NS doesn't serve Dahlgren. In fact, nobody does. The old RF&P Dahlgren Branch was cut back a long time ago. I think this happened before CSX took over RF&P. Tom
Maybe I'm misunderstanding something. NS doesn't serve Dahlgren. In fact, nobody does. The old RF&P Dahlgren Branch was cut back a long time ago. I think this happened before CSX took over RF&P.
Traveled up the NS Delmarva Secondary after barging across.
I'll see if I can find some pictures.
mlehman. I had a great-uncle in the Coast Artillery. I always thought that was a pretty safe assignment to spend a war, but I digress.
It was a hot humid day and I tried to comprehend, and really couldn’t, how the New Zealand Army gunners manning the two 6 inch guns, of 1900-01 vintage, stuck it out, especially before the Battle of the Coral Sea, waiting for a Japanese Imperial Navy task force to appear over the horizon complete with 8 inch gunned cruisers, not to mention the carrier based aircraft.
poppylI believe that the 280 mm gun did get prototyped but ended there. Long Tom was the largest nuclear rail gun that actually fired a live nuclear round.
Not the gun assembly itself, just the turret housing. NS hauled a sixteen inch gun tube (no turret) out of Dahlgren a couple of years ago on two "regular" flats.
I believe that the 280 mm gun did get prototyped but ended there. Long Tom was the largest nuclear rail gun that actually fired a live nuclear round. Eight inch and 155 mm warheads were the only nuclear shells that saw an extended stockpile life.
My error on the CG -- it's OUO and exempted from FOIA in its unredacted form.
When your schedule permits and it you haven't already, some good sources for historical information on the early AEC would be the DOE historian, Library of Congress, National Archives, and Smithsonian.
I wasn't sure much from those size guns would fit the depressed center, but I'll take your word for it they made it fit.
AFAIK, never any plans for a rail mount for the 280 mm. It was very much an interim weapon and I think if not for the Army's enthusiasm, the AEC would've preferred they skip that one entirely. I know the Air Force felt that way, because that projectile was a wasteful fissile material hog. But they whined about a lot of things everyone else did mainly because they wanted it all. By 1956, didn't much matter, because there was plenty to go around for everyone.
Yeah, agree no RD for the flatcar itself post-Trinity, in part because RD hadn't really been inveneted yet, although other systems obviously applied. I just brought it up to point out that it wouldn't make sense that it held anything that secret in itself, cargos excluded.
Got various classification guides, at least ones that they turn loose to we civilians. AFAIK, RDD-8 was the end of the line for the RDD series from DOE. Not sure what NNSA or however that whole angle is constitued and managed now. I'm pretty much anything up through 1964, so other things of a later vintage aren't really that useful for my work with certain exceptions. When the diss gets done, I'll have more time for catching up on things like flatcars, etc. I'm not in position to chase much down, with the exception if was somehow at Crane, which would not seem to be the case from what I understand about past ops there, given the Navy is mostly out. My niece works for the Army there.
Mike;
Your tenaciousness in your research is to be applauded. I would suggest a couple of areas that you may wish to delve into in learning more about the railcar -- other wartime uses (besides Jumbo) requiring such a weight capacity (sixteen inch or 12 inch main battery housing, for example), post war uses (tested rail mounted nuclear cannon maybe), and any connection to the Naval Nuclear Propulsion program on either the AEC or US Navy side. Where the car sat from 1945 to the late 40's/early 50's might also be illuminating. A history of the facilities that I referenced in my last post might help you, too.
BTW, RD should play no role in this but there could be some FRD in the Naval Reactors area. The CG has been updated since 2002 and I'm surprised that you haven't come across the update.
In matters like this I’ll certainly not be upset if my (hopefully educated) conjecture is proved to be totally wrong. Big Smile mlehman Lots to ponder there “The thrill of the hunt”.Smile, Wink & Grin
You're definitely not totally wrong here. In fact, mostly right. I just suspect that they saw no need to build a new center section/platform, which would have taken longer when they under extreme time pressures. It was quicker and cheaper to reinforce an existing car than build new.
l looked at the size of the JUMBO and compared it to platform length. The 25' length may have been mostly the center section. I'm pretty sure they didn't count the entry plug on the left side in the length. Diameter was 12', which looks about right versus pics of people around it. Given that, I'm guessing the platform is about 18' long, which is a pretty average length for these cars. B&O FDs averaged around 20' platform length. Others were in the mid-20' range. The shortest listed in my 1953 ORER was the MILW Road's 16 foot long one.
mlehmanThat is a chain of interesting observations
mlehman but it looks like the car has two six-axle trucks under each span bolster IMO
mlehman I have a little different take.
mlehmanLots to ponder there
However, on closer study of Mikes original photo, I believe there is evidence that suggests that the car was definitely modified to carry JUMBO. I am referring to the butt weld on the actual body/deck, (my apologies if I am using the incorrect terminology) at both ends of the top of the depressed centre portion. So, IMO, the trucks, span bolsters and deck ends of the car are of 2-41 manufacture, and the depressed centre portion is the later addition. (As an aircraft engineer, those welds bothered me, from the point of view that I expected to see additional doubler splice plates, but as I understand it, Butt Welding had become a perfectly accepted practice used extensively in the construction of the Kaiser Shipyards Liberty Ships.) Cheers, the Bear (Muddier of the waters).
That is a chain of interesting observations. I have a little different take. I suspect that what you're seeing are the reinforcements welded over the original structure. It's not so much that the car in the middle was replaced, but that it was modified. The length of the platform isn't really extra long, in fact would be on the short side if much shorter. I don't think length was the issue as much as strength.
Obviously, such a modification would result in a modified capacity. That update may never have made it into the ORER, by intent or oversight. So we are likely looking for a car with less capacity.
I saw that the NPS wide angle photo is the one used un the Chapter 10 selection; it's on page 14. This is a better copy than the one I first cited. Zooming in 400%, I can almost see the reporting marks/car number, but no. And it looks like it might be Robert Oppenheimer himself standing in front of the crane there on the left side. Looks like his hat and stature anyway. I would make sense that he was traveling with a photographer, too.
I don't know if anyone has said so already, but it looks like the car has two six-axle trucks under each span bolster IMO. There are obstructions due to the crane, etc, so not sure, but that would make sense more than a 2-axle and a 3-axle under each end which is sometimes employed, due to the extremely heavy nature of this load.
Lots to ponder there.
DSchmitt Photo: Hauling JUMBO on trailer from railroad to test site. http://www.brookings.edu/about/projects/archive/nucweapons/jumbo
Photo: Hauling JUMBO on trailer from railroad to test site.
http://www.brookings.edu/about/projects/archive/nucweapons/jumbo
DSchmitt and Bear,
Thanks for adding those directs links to how they got JUMBO from the RR to near Ground Zero. The trailer is the one by Rogers of Pennsylvania, which I referenced in an earlier link: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=12&cad=rja&uact=8&ved=0CDgQFjABOAo&url=http%3A%2F%2Fwww.rogerstrailers.com%2Fhistory%2FHistory-of-Rogers-Brothers.pdf&ei=olBsVMmJLYWlyATf9YDIAg&usg=AFQjCNHam_wfr1-fR3QW7y8Z1hWo7cAjCg
Yeah, a lot of stuff is familiar here, although most of my research runs after WWII. Another very interesting book, especially if you want to know more about the science and the technical problems they overcame along the way, is a book by my adviser, and three of her colleagues, who led the team that wrote the first declassified history of that aspect of the project, Critical Assembly: http://books.google.com/books/about/Critical_Assembly.html?id=KoTve97yYB8C
Which reminded me that most of the archival pics we're discussing may have been declassified for the first time for that book project, as much of the rest of the materials were back during the 1980s when much was just starting to be released on the Manhattan Project.
That was all pretty secretive until then, as you probably know regarding many details about the bomb, but given basic scientific knowledge is always advancing, after awhile even secrets like that become less important to stay secret. I mentioned earlier how nuclear info, formally known as "Restricted Data," is different than most secrets the US keeps. Other secrets are typically subject to regular downgrading as the years pass and are eventually declassified altogether. Restricted Data, on the other hand, has no timeline for declassification. And they track carefully what's declassified and what isn't. What is now open is compiled into a book called the Restricted Date Declassification Guide. The final one, from what I understand, is the 2002 edition, RDD-8: http://fas.org/sgp/othergov/doe/rdd-8.pdf
Why point this out? because it makes no sense for the info about this car to remain secret. I suspect if we can get a good copy of the NPS pic that is a wider angle view of the car at Pope siding, we'll be able to see the road number and reporting marks. The two different angles may have been taken expressly so that one image could be more easily releasable or they may simply have been noticed as different and classified differently originally because they wanted to suppress the indetifying marks. In any case, there's no good reason why it would still be bclassified at this point, but may have simply fallen through the cracks in the system and become an orphan that no one remembers, except to say it was darn secret at one time. Certainly even before Critical Assembly was published (1993, paperback edition - 2004) it was declassified so the pic could be used in the book.
To quote from “Manhattan, the Army and the Atomic Bomb” by Vincent C Jones, page 512, “In early June “Jumbo” the huge steel container to be used in exploding the first atomic device, arrived at Trinity. General Groves had maintained a special interest in the design, procurement, and shipment of the vessel, which was moved in early April on a special railroad car from Barberton, Ohio, via a carefully planned route to a railroad siding at Pope, New Mexico. There Trinity workers loaded it on to a massive trailer........”
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
7j43k Mike, I like your tenacity. You are right in noting that we civilians (in the broadest sense) sometimes see and/or take pictures of unusual military events. Info is where you find it. This is a GREAT topic! Ed
Mike,
I like your tenacity.
You are right in noting that we civilians (in the broadest sense) sometimes see and/or take pictures of unusual military events. Info is where you find it.
This is a GREAT topic!
Ed
Ed,
Thanks, I'm going to remember that in the morning when I'm struggling over my dissertation. The end is near, just not sure if it's for it or me...
I'm a bit surprised this hasn't been tracked down before, but there's a lot of weird little secrets out there that have just fallen through the cracks. Anything nuclear is especially prone to this, not because of the subject matter per se, but because there's a whole different set of rules for nuclear secrets versus "ordinary" secrets. Someone thought it important that as few people as possible know this and that's the way it often stays unless a historian or another interested party comes along and files an MDR, etc.
I did have another thought oin the numbers off the car. What if they didn't have a car with sufficient rated capacity? There was a war on, dont you know. Get the biggest car you can, then stencil an "improved" capacity on its sides in case any RR people along the way questioned it, or why it wasn't in the ORER, etc, etc. I'm sure this thing was probably a special move and very well minded at low speed, so the risk of a mechnical failure and the basically undamageable design allowed them to limp JUMBO across half the country -- because they had to.
Then there's those damaged bridge stories. That just didn't sound right to me and after more thinking, I think I know why. As a special move, the whole point was to avoid bridges like that. I'm pretty sure this is the sort of thing that Groves would've had at least one representative aborad. It never would've got near any marginal bridges, I'd think. So until I see more on that as proof, I' don't really believe that tale.
Or maybe not, but a couple of more theories to consider in accounting for why this car seems to be missing from the ORER, etc.
Yeah, if it was a Navy car to begin with, after Groves and Co. were done with it, reverting to the Navy but in nuclear duty, so to speak, would keep it busy. And off the books. Of course, there's nearly a decade-long gap between JUMBO and when the Navy started needing its reactors trundled around, so it had to have been somewhere in between?
I don't think we're certain it was a Navy car yet, at least from the picture at Pope siding, but if you do have some memory of it, somehow...that does need to be figured in. The color is still a bit uncertain. I found references to WWII Navy cars in blue, silver, yellow and black (I think that was it, but a fourth color anyway.) The car at Pope siding sure wasn't blue or black, could easily be silver, and I'm not sure how yellow would show up on B&W film (anyone know?) but there's the possibility of that.
Surely there must be some public record or pics of it. While a car can be obscure and travel the nation's rails, being completely secret seems to be a different matter entirely.
And its prior use would seem to be a mystery too, if it was a Navy car. What weighs half a million pounds and can fit on a rialcar? An anchor? I thought about gun turrets, because I'm from southern Indiana and Crane does (did) gun turrets, but only 5" and below. The Monon usually hauled them out of there from Bedford, although some may have stayed on the MILW Road. Retired Monon crews talk about needing to walk the train through one bridge because of the overhang on the turrets, so I doubt that anything bigger than 5" went through there. And they weren't heavy enough to rate a car like that.
So the mystery continues
The Jumbo shot was originally scheduled for about the time Trinity was detonated. If Jumbo had been executed, Trinity would have been delayed several months to recover and reconstitute the Pu from Jumbo. War Department and WH did not want to wait that long.
My error on the fate of Jumbo. It was destroyed in either the Able or Baker test in the Pacific in 1946. BTW, Jumbo was severely cracked in Trinity but not deformed.
In terms of the railcar I believe that it hauled some of the early Naval Reactor core assemblies and/or reactor housings between the AEC's NRDS in Idaho, the Bettis Atomic Power Lab, the Knolls Atomic Power Lab, and B&W. I do not believe that it every saw duty at Hanford but I'm working from memory and second hand information.
I've been looking over the Hanford leads and it's not promising. There is some RR preservation work going on, but no compiled info on the fleet over the years. Lots of pics and old RR equipment, but nothing really like the JUMBO DC flat. Here's some worthwhile links for RR history there.
http://www.atomicheritage.org/preservation-hanford
http://www.atomicheritage.org/sites/default/files/attachments/pages/Train%20handout%20Final%20for%20Web.pdf
http://www.rrpicturearchives.net/archiveThumbs.aspx?id=43745
A link to a pic of one of the other earlier "canyons" where the fuel rods werre processed to retrieve the Pu-239. I think I have a postcard of this one in a slightly different view sent by a worker there to a relative or friend.
http://digital.hagley.org/cdm/singleitem/collection/p16038coll2/id/2322/rec/22
Lots more about those RR-served canyons...
http://www.bonestamp.com/sgt/facilities.htm
Locomotives of Hanford (but not flat cars... )
http://sdp45.blogspot.com/2012/02/locomotives-of-hanford.html
This one could keep yuou reading and/or listening a long time.
http://www.manhattanprojectvoices.org/
Poppyl,
Yeah, I didn't want to get too far into the technical side of things, given it gets really deep, really fast. That's basiclaly what I was referring to as greater confidence in the technical design or whatever I vaguely referred to it as.
I think there was certainly pressure there in terms of time, but JUMBO arrived about 2 months before the scheduled date of TRINITY, so it never would've held things up in terms if its availability. Rigging the gadget into JUMBO might have taken some time, though, so yeah, that would've delayed things.
I would note that JUMBO survived TRINITY just fine. If it had been used and the test was successful as it was, yes, it would've been vaporized. It was designed only to contain the explosion of the conventional explosives used to compress the nuclear fuel. But it wasn't. Instead, they made a gesture at using it for something by hanging it in the fixture designed for it, mostly just to see what would happen.
Knocked the tower all to heck, but JUMBO just sat there where it fell.
Legend has it Groves was worried about someone making an investigation about why the money was spent if it wasn't used, so he sent a couple of engineer corps officers down to blow it up. They managed to knock the ends off by exploding 6 500-lb bombs in it. The rest was buried until a local offical inquired about it. It was located and dug up and what's left sits there on the edge of the federal property if you want to visit it.
Your point on the flatcar is well taken. It could've ended up recycled into the AEC, most likely at Hanford. That needs followed up on. However, that doesn't explain how the car came to be and what its orginal lading was intended to be. In Feb. 41, the MED was a long way off. JUMBO didn't come along as an idea until 1943 IIRC. Which is not to say that it didn't go to the AEC, just that it doesn't explain the origin of the car.
Interesting topic. Let me throw a little more coal on the fire. Your description of the intended use of Jumbo is basically correct but the original engineering aim was to test the smoothness of the gadget's detonators with a quantity of Pu that would not attain criticality upon compression. The containment would allow the quantity of Pu to be recovered and reused. Fairly late in the game the firing team conducted an experiment at Los Alamos that gave them a high degree of confidence in the perfromance of the firing system that the "full up" experiment was not needed. Pressure to weaponize the gadget on an accelerated schedule also played a part. Jumbo disappeared in Trinity, BTW.
The car built in 1941 was significantly modified (by B&W, I believe) to handle Jumbo so I'm not surprised that you can't locate it directly. However, as far as I know, the car remained after the war, perhaps in the Albuquerque or Idaho Falls areas, and I suspect that it may have shown up on the AEC property records beginning in 1948.
Hope that this helps a little.