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Tank cars - A missing link???

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Tank cars - A missing link???
Posted by Piper106a on Saturday, October 3, 2020 7:50 PM

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???

 

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Posted by RR_Mel on Saturday, October 3, 2020 8:03 PM

I found these articles with a Google search.

http://www.petroleumhistory.org/OilHistory/pages/TankCars/Evolution.html

https://en.wikipedia.org/wiki/Tank_car




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Posted by Overmod on Saturday, October 3, 2020 8:15 PM

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. Wink

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Posted by NHTX on Sunday, October 4, 2020 10:21 AM

     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.

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Posted by Lastspikemike on Sunday, October 4, 2020 11:22 AM

And value of any product carried by rail is by weight.

"Weight" is a stand in for mass and mass is what you want to pay for.

It has always been illogical to buy and sell liquid and gaseous fuels by volume. Solid fuels were always sold by weight. Fuel gases are priced by BTU or similar energy units which is another stand in for mass. I know natural gas appears to be priced by volume but it isn't actually.   

For rail freight mass is weight.

Alyth Yard

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Posted by dknelson on Sunday, October 4, 2020 12:15 PM

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.

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Posted by Overmod on Sunday, October 4, 2020 1:13 PM

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.

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.

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Posted by Lazers on Sunday, October 4, 2020 3:56 PM

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. Wink

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".

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Posted by cv_acr on Monday, October 5, 2020 9:44 AM

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.

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.

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Posted by cv_acr on Monday, October 5, 2020 9:50 AM

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.)

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Posted by Overmod on Monday, October 5, 2020 10:22 AM

cv_acr
On the other hand I filled up my propane tank for my barbeque on the weekend and was charged for 11 *pounds* of LPG.

That's because volume doesn't work for what is basically a gas liquefied under pressure.  Flow meter won't work; tank is opaque and irregular so can't be calibrated like labware; external 'liquid crystal' level gauges aren't accurate.  So the more sensible alternative, weight, is used... because it's easy just to purge the tank, plop it on a scale, and fill by display.

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...

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Posted by Lastspikemike on Monday, October 5, 2020 2:17 PM

cv_acr

 

 
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.

 

 

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.

 

Just read the fine print on the pump someday.

Gasoline and diesel are sold on temperature corrected volume. In Canada that's as if the delivery temperature were to be 15C.

So, fuel is sold by mass. The consumer just doesn't realize that because the "measured" and displayed numbers always look the same. The actual physical volume of fuel delivered changes.

If you know of a way to calculate a volume adjusted by temperature without any reference to mass let me know.

Natural gas is extracted, processed, pumped by compression through the pipelines and sold to the consumer "by volume". Except it isn't. All the adjustments made are by mass and although natural gas is mostly methane it isn't 100% methane. It is adjusted for energy content, and priced accordingly, per MMBtu as it happens. (Weirdly because the British no longer do, they price natural gas by the Kwh)

It is quite noticeable at your natural gas BBQ if you get a batch of relatively low energy natural gas, if you are observant. Your BBQ does meter out gas by volume using a relative pressure regulator.  It can be a bit annoying. The gas meter on your house is temperature compensated, the upstream pressure is known. Nevertheless the final volume charged to,the customer is not the "actual" voLuke, whatever you think that might mean. The consumer charges are adjusted for mrssured  thermal value of the gas at time it is pushed into the domestic distribution system just as it has been right from the wellhead. Only an idiot or a politician values a bad by volume. Natural gas producers are not idiots nor are they politicians, every molecule of burnable gas gets accounted for somewhere. 

Pricing is in fact by energy content, just as for gasoline, but that reality is disguised for the consumer. Why is a good question.

For the railroads they care only about the weight. They love natural gas because it lifts the tank cars and that generates huge profits....truckers love transporting chickens for the same reason although it is very annoying to have to keep stopping every 10 miles (16 km). 

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Posted by SeeYou190 on Monday, October 5, 2020 2:29 PM

Piper106a
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???   

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

Wink Happily modeling my STRATTON & GILLETTE RAILROAD. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by cv_acr on Monday, October 5, 2020 3:26 PM

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?

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Posted by Overmod on Monday, October 5, 2020 3:32 PM

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?

As he would say:

https://m.youtube.com/watch?v=8JtnEUPvpus

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Posted by SeeYou190 on Monday, October 5, 2020 3:35 PM

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?

 

OMG ROFL

Overmod
As 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.

-Kevin

Wink Happily modeling my STRATTON & GILLETTE RAILROAD. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by Lastspikemike on Monday, October 5, 2020 5:05 PM

Sad indeed. You read all of my posts with almost obsessive concentration. 

Perhaps if you would quote me in context.

I am not wrong because I change my mind when new information comes my way. Before that I am, of course, always corrct in what I say. In the case of expression of opinion correctness is irrelevant.

The majority of consumers are happily unaware of the fact that they are charged for volumes of fuel not actually delivered. Good thing too as  charging by actual as measured delivered  volume would be dishonest. Gives you a whole new perspective in those old gas pumps which really did deliver by uncorrected messured volume. On a really hot day your fuel economy would seem very poor. Not any longer, a gallon of gas is really a gallon, er, by mass (6 lbs according to Wikipedia).

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Posted by Lastspikemike on Monday, October 5, 2020 5:13 PM

CNG isn't shipped by rail as far as I know. If it were the loaded tank cars would not be very heavy apart from the robust construction required. Mind you, CNG would provide quite a bit of structural support for cylindrical tanks with domed ends. About 1/5 the "weight" of an oil tank load (at 200 to 250 bar). Keeping it cold enough is tricky when using rail transport. 

Here's the bumpf: 

https://fas.org/sgp/crs/misc/R46414.pdf

Presumably the ultimate size and tare weight of any given tank car would depend on the expected loading.

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Posted by SeeYou190 on Monday, October 5, 2020 5:19 PM

Lastspikemike
I 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.

-Kevin

Wink Happily modeling my STRATTON & GILLETTE RAILROAD. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by Lastspikemike on Monday, October 5, 2020 5:23 PM

SeeYou190

 

 
Lastspikemike
I 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 and needs to be retired.

-Kevin

 

Your now blunt accusation is not supported by the facts.

In addition, by making this totally unwarranted personal attack you reveal an obsessive attention to my posts, which is incomprehensible under the circumstances. I suggest you desist. I will do the same for you.

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Posted by Overmod on Monday, October 5, 2020 6:24 PM

SeeYou190
Nope, he's always right remember. You just can't keep being wrong about everything and then say "It was a joke".

I actually thought it was pretty funny, and played off the tech hyperbole about measuring the lift of the special calibrated gas-line segment and totalizing to get the billable delivery.

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..."

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Posted by Lastspikemike on Monday, October 5, 2020 6:36 PM

Overmod

 

 
.

How will he ever learn to stop making mistakes unless we help him and help him and help him learn?  

 

Exactly what I said. 

I can't recall just off the top of my head whether it was Sir Winston or Richard Feynman with the  quip about changing your mind when the facts changed.

At least we aren't trying to discuss alternative facts. 

It was Churchill. 

Feynman'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....

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Posted by Overmod on Monday, October 5, 2020 6:47 PM

.

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Posted by Overmod on Monday, October 5, 2020 6:50 PM

Smile

Lastspikemike
Feynman'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....
All the Feynman books are wonderful - I recommend the 'adventures of a curious character'.  The best thing about Feynman is that he never stopped being a Brooklyn wiseguy at heart ... and never to my knowledge acted as if superior to anyone.  We lost him far too soon.

(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:

lastspikemike
It was Churchill.

It was Keynes.

And you claim to have been brought up British??? ConfusedSmile

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Posted by Lastspikemike on Monday, October 5, 2020 6:56 PM

Let us not forget the wonderful ether wind which was proved to be imaginary by that seminal Michelson Morley experiment that got Albert thinking in the first place.

All this time later we still refer to radio as being broadcast over the ether....

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Posted by Overmod on Monday, October 5, 2020 7:01 PM

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"?)

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Posted by Lastspikemike on Tuesday, October 6, 2020 9:08 AM

Overmod

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"?)

 

I'd have to look that up. Microwave oven frequency would work....

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Posted by Overmod on Tuesday, October 6, 2020 9:25 AM

Lastspikemike
I'd have to look that up. Microwave oven frequency would work....

Aha!  I see you're thinking...

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. 

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Posted by tstage on Tuesday, October 6, 2020 11:22 AM

If you two are done hijacking the OPs thread, can we get back to the original question and discussion?  Thanks...

http://www.newyorkcentralmodeling.com

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by Overmod on Tuesday, October 6, 2020 3:10 PM

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?

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