Besides covered hoppers, tank cars are my probably my favorite rail cars. However, I have also wondered this - can tank cars only carry one type of product, or can they cary whatever is in their “catagory”? For example, certain cars may be for petroleum products, that is, they can carry oil, gas, diesel, ect. Other cars are made for food products, and they can cary canola oil, vegetable oil, corn syrup, ect. And so on and so forth.
I had thought that they can carry only 1 type of product, however, in the BNSF OK derailement thread, someone said that there was hydrochloric acid residue in one of the ethonal cars.
So I suppose this means that they can carry different product?
I would say that one’s that are in food service will only be in food service.
Those in chemical or petroleum will stay in chemical or petroleum service. food grade and chemical will not mix.
If you notice some tank cars have stencil painted on them what they are loaded with. such as vinyl chloride or Hyrochloric acid etc. sometimes these are painted out. i believe that these care once empty can be cleaned and loaded with a different product. Car caring LP gas will only carry LP gas as they are a presuurized specialty tank.
I always understood that a tank car stenciled for a particular product was always going to carry that product. Even though the cars can be cleaned, can they be cleaned enough to prevent a chemical reaction if a car is loaded with another product, different from it’s previous load?
Tank cars are generally not used for more than one product without an intermediate cleaning due to contamination and loss of certainty about the product, leading to loss of liability if the product is defective.
Tank car types are usually designed for specific commodity groups even in the non-pressurized general-purpose cars, as the densities of different liquids vary; DOT/AAR/FRA requirements on venting, valving, insulation, head shields, and other characteristics vary; and so forth.
Tank car cleaning is common but not inexpensive and it is not done without a fairly large economic incentive.
There are several hundred tank car types in use.
I find it hard to believe an ethanol car was previously used to carry hydrochloric acid. The car types are completely incompatible. Ethanol moves in a 29,000 or 30,000-gallon general purpose, non-insulated car, bottom-unloading car, whereas HCl moves in a 20,800-gallon rubber-lined, bottom-sloped, top-unloading car specifically designed for HCl. Putting ethanol into an HCL car might dissolve the lining, wheras putting HCl into an ethanol car might dissolve the tank itself. A car built for ethanol can (usually) also carry gasoline, metha
Generally speaking, tank cars are restricted to one specific service, and this is usually dictated by commodity properties (density, corrosive, ambient vapour pressure, etc.), and how the car is correspondingly outfitted: pressure car or not? Rubber-lined (like hydrochloric) or not? length? fitting types? Tank material? While hydrochloric acid and ethanol cars are both non-pressure, hydrochloric acid would attack the ethanol car, as it is not rubber-lined. Also, the the length of the cars is proportionate to the commodity density/volume. For example, a sulfuric acid car is much shorter (i.e. smaller volume) than an LPG or glycol car. Sulfuric is about 18 lbs/gallon, whereas LPG may only be about 4 (or thereabouts, i think). Also, most cars (in fact, all regulated commodities) are limited to 263,000 lbs GRL, while very few porducts (clay slurry, corn syrup, vegetable oil) are able to have 286,000 lbs GRL. Also, most tankcars are lessee-owned, and consigned to a specific customer. The customer will generally only use the car in a specific route/service, and will likely specify certain options on the cars that could limit or make the car unfavourable for other commodities. That being said, some cars can be converted (i.e. clay slurry to sulfuric acid). One common example of a car that is used for two different commodities is an LPG/Anhydrous ammonia car (with the obligatory cleaning, of course).
My brother tells me of a specialty petroleum products company that ships from Texas to North Jersey. Along the way they stop at a mixing plantl. Once upon a time they unloaded the cars, put in some additive, agitated the mixture, loaded it back into tank cars, then sent them the rest of the way to North Jersey.
Then they discovered that all they needed to do was put the additive into the tank car. The cars rocked and vibrated enough in transit from the mixing plant to the destination so they didn’t need separate agitation.
The Topicana orange juice unit train is not tank cars, they’re special box cars with a set of some kind of tanks inside. Is that close enough to tank cars for this thread? But I understand instead of, or in addition to, cleaning the cars in North Jersey they send them back to Florida full of water, which then contributes to the drinking water system there. If that’s true then the quality of local Florida water, the fact that one has to fill the cars with water anyway to rinse them between trips, and the cost to move the load of water south vs the empty train all conspire to make it worthwhile.
I’ve tried the “what valuable liquid they send back to Florida” quiz with folks. Northerners rarely guess water, Floridians often figure it out, so it looks like treated drinking water is harder to get in Florida than in the northeast.
One of my major customers was a tank car manufacturer and I spent considerable time in their manufacturing facility. I never took the time to understand the necessity of the different hardware and the pressure/nonpressure aspect of the cars.
I do recall the same tank car spec could be used for Anhydrous Ammonia and LPG…just a change in the commodity decals were required.
Interesting how a car is usually in a pattern movement between shipper/consignee.
Would there be much of a use for nonpressure ethanol cars for other commodities? What alteration would be necessary? There was quite a buildup 12 months ago, but it died down rather rapidly.
RWM and Moonie, between the two of them, have said pretty much everything I was going to. I have seen cars whose intended commodity has been changed, but it’s not done without a thorough cleaning and (usually) a repainting on the outside. Best example is the UTLX 24000-series tank cars, nearly all of which were used for clay slurry or limestone slurry. That business seems to have fallen off of late (differences in paper production?), and I’ve seen these cars modified to transport sodium bichromate or phosphoric acid.
A curiosity: it’s easy enough to tell, with a casual glance, the pressure tank cars such as those used for LPG or anhydrous ammonia. Several times in the past, and once within the past couple of weeks, I’ve seen some former LPG cars (commodity stencil painted out) being used to carry a non-pressure commodity, specifically gasoline <1203>. I believe it’s called pyrolysis gasoline, though I didn’t see that commodity stencilled in this latest batch of former lpg cars (UTLX and PROX, I believe). The cars showed up on my report as “Flammable Liquid” inteasd of “Flammable Gas”. I don’t know if these commodities can be freely carried alternately in these cars, but I didn’t see any evidence of modifications on the cars themselves–they still look like pressure tank cars.
Interesting comment about possible paper production reduction. Does anyone know if there has been a reduction in paper production? It would make sense.
On a related subject, has there been any further developement of the new tank cars? I recall there was a joint effort between a couple of manufacturers and AAR in developing a super tankcar.
I think you either misunderstood what was said, or the report was incorrect.
Either that, or the person you overheard was incorrect in what they said.
What I heard on the new blurbs was tank cars of ethanol were burning, and a tank car of hydrochloric acid residue was also involved in the derailment and close to the burning cars.
It is not unusual for several different commodities to be grouped together in a train…not all the tank cars you see in say, this train, have to carry the same product.
You will find them usually grouped together by destination, which often means they are often grouped together by product or commodity, but it is normal to find molasses cars, tallow cars, corn sweetener and such running in the same train as gasoline and diesel, ethanol and other “fun” stuff.
I doubt anyone would load hydrochloric acid in a tank car designed for ethanol, simply for the reasons already stated, it would require the car to be cleaned, re stenciled and re assigned in service.
What has you confused might be a simple matter of semantics.
If you want a ton of information on tank cars, here is the Power Point from the U of I’s Chris Barkan on his his Sandhouse Gang presentation on the work he and his grad students did on tank car safety.
Unless its changed, I was not aware that Tropicana’s boxcars have tanks inside them.
From my knowledge (Including watching a DVD about the Juice Train, and researching it on the internet) the cars are simply reefers that are loaded with wooden palets of shrink-wrapped orange juice cartons. The CSX cars on the front end of the train (usually) are insulated cars that carry other non-perishable goods such as Tropicana Twister.
Probably not, at least not in revenue service. I assume you’re thinking of the ones Linde (and other companies) used for carbon dioxide and other such gases–they were retired decades ago, due to old age. There were also some mechanical reefers owned by Fruit Growers Express that had been rebuilt with tanks (or one large tank) in them for beer–they were lettered with large “The Chiller” lettering. Anyway, those were converted back to ordinary mechanical reefers years ago. A lot of them are now operated by UP in the ARMN 933900 series (a few in other series, perhaps); the hatch in the roof is their distinguishing characteristic.
The Linde cars were considered to be tank cars toward the end of their careers; prior to that they were called “box tank” cars (AAR Mechanical Designation XT). The Chillers were never anything but refrigerator cars (albeit with their own Mechanical Designation, RPC).
Not sure whether it’s a reduction in paper production; perhaps it’s a conversion to powdered clay as opposed to slurry. Might conserve more water that way. Or maybe the WC/CN just took all of that slurry business away from us. I do know that a lot of companies that used to have prominent lettering on the sides of their tank cars are no longer in the business.
Haven’t heard too much about the new-design tank cars. UP and Dow Chemical (perhaps among other companies) were supposedly developing the new standards, but I’ve heard nothing new lately. A couple of companies–DuPont and Olin–have been well known in the past for “overbuilding” their tank cars to better withstand the ordinary and extraordinary rigors of railroad operation.
I see a great deal of ethanol shipped every day. I kept track of the cars manufactored by Union Tank, Trinity, and ARI. They are of the General Purpose type tanks. Most anything that is non-corrosive and not under pressure may be shipped in them. However, once loaded with a commodity, they cannot be loaded with anything else unless they are cleaned.
Cargill in Blair took delivery of a group of tanks in the UTLX 6687xx series in 2006. They shipped ethanol in them for a time. Union Tank had those surplus at the time, and the order for Cargill was backlogged. Once the order was delivered, Cargill returned the 668xxx cars, they were cleaned, and sent into nitrogen service.
Especially food products. Using a tank car to transport another kind of food without some kind of extremely thorough cleaning might lead to contamination. Though this isn’t related to rail cars, back in the early 90s there were incidents of salmonella with Schwan’s ice cream. IIRC, the ice cream ingredients were transported by tanker truck, and that very same tanker was also used to transport raw eggs, a prime culprit for salmonella.
Tropicana did experiment with shipping using a refrgerated tankcar. It must not have worked out. However, it is still listed in the January 2008 ORER (TPIX 6000). Unfortunately, I have never seen a photograph of it.
It is common for those type of cars to carry flammable liquids out here. By far the most common are pentane and 3295. Although gasoline is also common. A few years ago I saw some placarded for natural gasoline. I also saw a couple placarded for gasoline but stenciled for LPG sitting at a refinery. Hopefully that was corrected before they left.
If the amount of vapor produced when heated is higher for the other commodities than for LPG, perhaps they might need to change the size of the safety valve, otherwise I cannot think of any modifications that would be needed, of course I am not an expert.
I think you read something into Videomaker’s post. He wrote that there were reports that HCl residue was in a tankcar. Nowhere was it said the car ever carried ethanol.