There seems to be a missing evolutionary step in tank cars designs.
For LP gas / propane cars, did the designs really jump from the 10000 to 11000 gallon cars with underframes to 33000 gallon cars without underframes in a single step???
In the same way, did chlorine tank car designs jump from 6000 to 8000 gallon cars with underframes to 17360 gallon cars without underframes in a single step?
Railroads seem to be very much evolution driven rather than revolutionary. In the case of both the LP gas and the chlorine tank cars, it would seem like there should have been some intermediate design between the 1950s era small cars and the large cars currently on the rails, but my google fu is weak and I have not been able to find such a intermediate size car.
Do you have pictures or links for the 'missing' designs???
I found these articles with a Google search.http://www.petroleumhistory.org/OilHistory/pages/TankCars/Evolution.htmlhttps://en.wikipedia.org/wiki/Tank_car
Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
Personally I'd date the structural changes to improvement in fabrication techniques, better full-penetration welding, and better steels.
Remember that the real innovation in these cars was not allowed to persist; look up the history of 'rail whales'. Any merely four-axled car is 'midrange' after that.
Railroads and modelers see tank cars through different points of view. Railroads are interested in the weight of a loaded car, instead of capacity in gallons, as most modelers are. The Official Register of Railroad Equipment which is supposed to list every car in interchange service in North America, gives the volume of tank cars in thousands of pounds. Very few list the volume in gallons-as well as with the thousands of pounds.
Due to widely differing pounds of weight per gallon of lading, we have vast numbers of different sized tank cars, dependant on gross rail loading or, how much a fully loaded car and contents can weigh and still be interchanged without restriction on the North American rail system. For a long time the universal GRL for a four axle car was 263,000 pounds. This has since been increased to 286,000 pounds for a four axle car. Nowhere is gallonage mentioned. That is the worry of the shipper and the carbuilder.
The "GATX Tank Car Manual, Fifth Edition, Feb. 1985", published by the General American Transportation Corporation lists hundreds of commodities shipped in railroad tank cars by pounds per gallon. This will explain why a car carrying sulfuric acid will be dwarfed by one carrying the same weight in liquified petroleum gas:
Product: Common car capy. in gallons Pounds per gallon
Corn syrup 17,600 11.66
Liquified pet. gas 33,500 4.24-4.83 @-58 degrees F.
Molten sulfur 13,550 15.0 @ 255 degrees F.
Peanut oil 25,500 7.67
Sulfuric acid 13,600 14.26
Water as required 8.33
Bottom line: The heavier the commodity in pounds per gallon, the smaller the car. Increases in gross rail loading limits and elimination of center sills permitted increases in load capacity while remaining within established limitations.
There were of course experiments with frameless tank cars going back even before WWI. But the modern frameless tank car pretty much followed the use of welded versus riveted tanks.
My hunch is that tank cars got larger to (try to) keep the traffic from truck competition, so maybe the missing link is to be found by looking at the size of tank trucks on the highways.
Dave Nelson
LastspikemikeI know natural gas appears to be priced by volume but it isn't actually.
Not that it is particularly technically difficult to build or deploy thermal mass-flowmeters, especially if they can be designed as 'smart' with the additional processing capability to correct for temperature and pressure variations... it's just not the done thing.
Likewise, there are notices in every gas station here that fuel is sold by volume, uncorrected for temperature and therefore explicitly not by mass.
Now, it's more likely that utilities making long-term contracts with gas suppliers might write provisions concerning mass-flow correction. Again if you have documentation of the details of this, I'd like to see how it is arranged and calculated. But consumer 'price' is determined only on volume.
Overmod Personally I'd date the structural changes to improvement in fabrication techniques, better full-penetration welding, and better steels. Remember that the real innovation in these cars was not allowed to persist; look up the history of 'rail whales'. Any merely four-axled car is 'midrange' after that.
Hi, that is how I would think modern Tankers evolved, thru modern design & fabrication techniques + better quality materials. I should think that T-cars are classified as Pressure-Vessels.
I looked this up in Jeff Wilson's 'Modern Freight Car' book. The transition to modern T-car design began in 1954, when Union designed and built the first modern Frameless car. No. 42998, no centre-sill or running boards.
However, it was not approved by the Interstate Commerse Commission until 1961 and that could account for why T-car design suddenly revved-up, the designs were there, but not fully in use?
It is worth noting that cars with Aluminium Tanks still have Centre-sills, also Co2 & Cryogenic liquid cars.
It must be good to design RR cars because as time moved on, you see how the designs were rationalised for quicker, cheaper production in the need to remain competetive on price, maintain AAR standards, but still deliver the shipper's goods. Paul
"It's the South Shore Line, Jim - but not as we know it".
Overmod Lastspikemike I know natural gas appears to be priced by volume but it isn't actually. To consumers, it most certainly is. If you know of a utility using anything other than volumetric flowmeters for premise consumption, tell me about it; all the ones I have seen including the newer 'smart' versions all read in CCF (this being Stateside in nonmetric units) and the billing is likewise relative to that reading, not adjusted to mass. ... Likewise, there are notices in every gas station here that fuel is sold by volume, uncorrected for temperature and therefore explicitly not by mass.
Lastspikemike I know natural gas appears to be priced by volume but it isn't actually.
To consumers, it most certainly is. If you know of a utility using anything other than volumetric flowmeters for premise consumption, tell me about it; all the ones I have seen including the newer 'smart' versions all read in CCF (this being Stateside in nonmetric units) and the billing is likewise relative to that reading, not adjusted to mass.
...
Gasoline and diesel fuel is definitely sold by volume (gallons in the US, litres in Canada).
My natural gas utility bill for home heating is in fact also measured in cubic metres (Canada). I assume that's calculated at a standard pressure and that's how it's represented on the bill.
On the other hand I filled up my propane tank for my barbeque on the weekend and was charged for 11 *pounds* of LPG.
Chris van der Heide
My Algoma Central Railway Modeling Blog
NHTX Railroads and modelers see tank cars through different points of view. Railroads are interested in the weight of a loaded car, instead of capacity in gallons, as most modelers are. The Official Register of Railroad Equipment which is supposed to list every car in interchange service in North America, gives the volume of tank cars in thousands of pounds. Very few list the volume in gallons-as well as with the thousands of pounds.
The ORER I have here absolutely lists both gallons and weight capacity in the table for tank cars - just as for other types of cars it lists cubic foot capacity as well as weight.
NHTX Due to widely differing pounds of weight per gallon of lading, we have vast numbers of different sized tank cars, dependant on gross rail loading or, how much a fully loaded car and contents can weigh and still be interchanged without restriction on the North American rail system. For a long time the universal GRL for a four axle car was 263,000 pounds. This has since been increased to 286,000 pounds for a four axle car. Nowhere is gallonage mentioned. That is the worry of the shipper and the carbuilder.
Yes, gross weight is the limiting design factor which is why cars designed for specific commodities range so much in size from 14K gallon sulphuric acid tanks to 33K compressed LP gas tanks in order to stay in the weight limit for a loaded car. (Which you basically stated as much - just reinforcing.)
cv_acrOn the other hand I filled up my propane tank for my barbeque on the weekend and was charged for 11 *pounds* of LPG.
Airplane fuel is critical, so it gets carefully measured ... by weight. You could do that with your car, too; it's how they tell how much old newspaper or whatever you brought to recycling in your pickup bed. But it isn't cost-effective to put automobile scales at every pump, and watch for scams...
... and of course differential weighing of an instrumented section of your natural-gas line to gauge the amount of mass passing at typical gas admission pressure, then integrating over time for a billing period is... not exactly practical...
Piper106aFor LP gas / propane cars, did the designs really jump from the 10000 to 11000 gallon cars with underframes to 33000 gallon cars without underframes in a single step???
If there was anything produced in mass numbers between these steps, I cannot find anything about those cars.
It makes sense that the jump could have been that large is the change from 50 ton loads to 70-100 ton loads took place the same time the heavy underframe was removed.
If so, they would have increased the total capacity of the freight car at the same time the "dead weight" of the car was decreased.
That could account for the jump.
-Kevin
Living the dream.
LastspikemikeFor the railroads they care only about the weight. They love natural gas because it lifts the tank cars and that generates huge profits
Um, what?
cv_acr Lastspikemike For the railroads they care only about the weight. They love natural gas because it lifts the tank cars and that generates huge profits Um, what?
Lastspikemike For the railroads they care only about the weight. They love natural gas because it lifts the tank cars and that generates huge profits
https://m.youtube.com/watch?v=8JtnEUPvpus
OMG ROFL
OvermodAs he would say:
Nope, he's always right remember. You just can't keep being wrong about everything and then say "It was a joke".
This is a tired merry-go-round we are on with him.
I am sorry I went back and read the whole thread. I should have just stuck with my answer to the OP and left it alone.
This is sad.
LastspikemikeI am not wrong because I change my mind when new information comes my way. Before that I am, of course, always correct in what I say.
This excuse for repeatedly and purposefully posting inaccurate information is no longer funny, if it ever was. This expression of yours has run its course with this audience and needs to be retired.
SeeYou190Nope, he's always right remember. You just can't keep being wrong about everything and then say "It was a joke".
The thing with the CNG tank actually had me thinking for a moment before I got the joke. You'd want to design it with camber for running empty, but normal camber would pull it the wrong way when pressurized to 3000psi or more. And that would be a lot of pulling.
How will he ever learn to stop making mistakes unless we help him and help him and help him learn? Like talking authoritatively about CNG and not noticing his reference involves LNG ... hey, gas is gas, right? Well, if we don't tell him no, he'll go right along shooting himself in the foot in his mouth. And it would be a violation of noblesse oblige just to shake the head or snicker quietly and think "there you go again..."
.
LastspikemikeFeynman's "Surely you're joking Mr Feynman" is a rollicking good read, even if you're not a physicist, which I'm not although I easily could have been....
(A far better quote along the lines of scientists' prerogative is an argument in one of Niven and Pournelle's Motie stories, where one character argues what happens when the observed data and the math don't match, and the other notes that it's usually the math that changes ... as was true for phlogiston, and induction, and relativistic effects, just to name three.)
BTW:
lastspikemikeIt was Churchill.
It was Keynes.
And you claim to have been brought up British???
Ah yes, the luminiferous ether. The dark matter of the late 19th Century. (I was tempted to say 'cosmological constant' but I am not that cruel a man...)
How fortunate for us all that Mr. Ockham developed his wonderful edged tool...
(Incidentally, do you know the frequency of Tesla's "death ray"?)
LastspikemikeI'd have to look that up. Microwave oven frequency would work....
Actually the effect is not in the GHz range because even with 'scalar' propagation you'd need enormous broadcast power in one of the atmospheric-moisture 'windows' to get any effect at distance. What Tesla discovered is much more direct.
If you two are done hijacking the OPs thread, can we get back to the original question and discussion? Thanks...
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
Right!
Has anyone looked at a car-builder's cyclopedia from the late '50s through the Big John years to see what sorts of intermediate designs predate the eight-axle whales?
Of course there were other cars that were by no means as stunningly capacious, but stop you in your tracks certain you're looking at some product of not very clever Photoshopping -- NHTX 26000x, for example. This is "only" 25,700 nominal gallons and 188600# load (could this be BTX?) but is 76'7" long (!) with the trucks under the extreme ends of the car (!!).
Meanwhile I can still remember the blue and white duPont tetraethyl lead tank cars at the Bayway refinery. Those might have been the smallest tanks in interchange service... assuredly not the lightest.