Tanker containers are handled in intermodal trains…it is my impression these are international in nature. The tanks are “framed” with support beams which appears to allow a double stacking. Yet, I have not noticed that these tank containers are ever double stacked. These containers appear to be 20 ft in length, certainly not 40 ft.
Are these tanker containers single stacked due to safety concerns/issues? Or is it just coincidence that I have not noticed double stacked? These tank containers seem to always be in the well of the car, not stacked. So, nothing on top of the containers and apparently not stacked on other containers.
If there is a restriction on placement on trains, does that restriction also apply on the container ships?
They are carried on the bottom when loaded for a simple reason. It’s called surge. Just imagine 3 to 4k gallons of liquid going back and forth and side to side around a curve. You want to keep it as low as possible tk prevent it from causing you to end up on your side. There’s a reason why liquid tanker driver’s are the 2nd highest paid in the OTR industry. They deal with products that never stop moving around and well except for explosives sometimes the stuff they’ll be hauling can and does kill.
Remember - on ships - roughly half the containers on the ship are hidden from view as they are down in the ‘hold’ of the vessel. We only see the containers that are above deck level.
I am certain container vessels have defined loading plans designating what kinds of containerized cargo get stowed in which parts of the ship - complicated by the fact that most vessels are in ‘liner service’ with multiple ports of call in their schedules, where they discharge and load cargo at each port. Where tank containers fit in this loading plan I don’t have a clue.
The frame is to provide four twistlock sockets at the bottom corners for securement and location, and four twistlock sockets for spreader lifting from above.
They are not stacked in the United States because the tanks are not hardened against puncture or penetration in handling. As mentioned, surge as well as roll are concerns that would keep them from ‘upper decking’.
Was watching the Deshler live cam this morning and noticed some tanks with containers on top going by. Can’t say I ever paid much attention until reading this thread but here we are
Today’s I10 thru Fostoria had a 40 ft tanker container bottom loaded in a well car with a 53 ft UPS container atop. If anyone wants to watch it …fostoria railcam at 12:13:42 on the east camera.
First time I noticed one. Snowdog…thanks for the visual.
Was riding with a crew in Cleveland that had to switch a chemical plant - one particular track had 8 spots for tank cars of various commodities. As I recall when we got to the plant each spot had a car. Our job was to pull the 7th car in the track and replace it with a car in our train. Each of the cars on the track were partial loads except the cars we were to pull and replace.
When we coupled to the first car we had to wait a period of time for the slosh (surge) to settle down before going to couple to the second car - and it took longer for the slosh to settle and so on and so forth until we coupled to the 7th car and pulled it from the train to set over so we could couple to the NEW 7th car and then re-spot the track. With more than two cars coupled the slosh would slide the train including the engine until it settled down.
A job that should have taken 15 minutes, because of slosh took over an hour.
Some tank loads can slosh laterally, which is not the direction most people think of ‘surge’ as acting.
I remember one car in Shreveport, which probably had not moved for hours, which must have had substantial free surface in a fairly viscous heavy medium. It was rolling, all by itself, with a period of about 45 seconds, far enough to cause substantial spring depression in the trucks. It might have been interesting to observe this car’s behavior when moving, especially in conditions conducive to harmonic rock.
Back in the 1960’s John Kneiling was proposing that many tank cars could be replaced by tanks in container frames. Interesting to see that has actually been put into practice.
Steam locomotive tenders had “splash plates” in the water tank. Also, tender trucks for passenger trains were of the swinging bolster type. Are these the same measures?
I used to play with bromine in tanker trailers for a customer I serviced years ago. My tanker trailer was rated for 6k gallons of water. I couldn’t even carry 2k gallons of bromine and was at gross weight. The surge on those loads was like getting kicked in the back by a freaking draft horse.
I assume the Bromine was elemental Bromine as opposed to a Bromine compound? Due to the density as hazardous nature, I’m a bit surprised that there aren’t dedicated tank trailers. OTOH, it’s better than hauling a tank full of ClF3 (Chlorine tri-Fluoride), which if spilled will cause the road to burn - that’s including concrete.
i would say for the most part its safety to keep them low to the ground imagine the liquid in then splashing against the side walls while being on the top part of a double decker bus since its higher off the ground on such a narrow vehicle its top heavy and easier to tip
add thousands of gallons of liquid splashing back and fourth to a already top heavy tank that has less balance cause its stacked higher its sure to tip. but thats what id guess at a glance
i just wish they would make tank cars for ho+ that held liquids especially some tank car i could use to refuel my chainsaw with
The tanker trailers need to be a certain length to comply with the federal bridge law so they can’t do what the railroads do and make them short and narrow. Now dedicated sulphuric acid trailers are narrow by design but they also are only hauling one product.
Wasn’t aware that trucking was using tank trailers as ‘free runners’ any load anywhere.
Considering the great variability of liquid load characteristics between acidic and caustic as well as the varying specific gravities of the various liquid commodities I would have expected the carriers using tank trailers to have them used in specific commodities and the tanks sized to the characteristics of the commodity being hauled.
Nope it’s rare that tank trailers are designed for specfic commodities. If you’re pulling hazmat loads you can go from acids in one load to alkaline in your next load a heavy liquid to a lighter one also. Then throw in stuff like petrochemicals.
Food grade one load could be corn oil then ulyour hauling corn syrup or orange juice to vinegar.
About the only ones really designed for a specific commodity are the cryogenic tanks. They require different amounts of insulation pressure relief valve pressures and different unloading fixtures. The biggest 2 are anhydraus ammonia and propane.
