Suggest your first check is to investigate the impact loading of a stream of material into your wagon according to the flow rate, then the impact loading of a single lump onto the bottom or side of the wagon. ■

Originally Posted by BabakHoudeh

What is the upper limit of common size iron ore to be

loaded into conventional rail cars. I was told that loading coarse iron ore (-300~+200 mm)

to rail cars needs heavier construction and and reinforcement.

The problem you are asking about is more complicated than

simply determining the ability of an open top hopper car of any type

to receive six inch plus run of mine iron ore.

You must determine if the railroad is capable of carrying this payload,

the railroad guage being narrow, standard, rack type standard and narrow,

and the indian "standard" guages as an example.

The wieght of the railroad rail PER FOOT, plus the actual "Tare" wieght of the

hopper car "PER AXLE" and the laden weight to determine if it is even possible

with a "small" low gondola car(rail wagon). This is a problem you cannot back into like

an algebra problem.

The other issue is the design of the unloading system with regard to a 40 foot "Low Gondola",

40 foot "Standard Gondola" with bomb bay doors, 40 foot Bathtub Godola,

50 foot standard gondola with bomb bay doors, Ore Jennies and the like.

The tail end of the dog involves unloading and the unloading method that needs to be

determined long before you begin his algebra problem and bring it to a problem with

a solution if one is available

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A capsule pipeline used to transport ores and waste rock for example has

no limits other than the available right of way, the inside diameter of

the capsule pipeline, and radius curvature which can be no smaller

than fifty times the inside diameter of the capsule pipeline where

the rate of incline, the allowable radius curvature for the railroad route

and also depends on the rail gauge, car length, and desired train speed.

Help us, to help you, help us help you! ■

Lump size and loading rate are not interdependent in this situation. Simply calculate the deflection of the wagon panels under the loading imposed by the largest lump. Then apply the 1/2 plate thickness criterion as used to be recommended in Roark.

If loading from a hopper then the initial loading rate will be less than the average design rate but the largest lump can drop direct onto the car floor. After that the energy will be dissipated through the bed layer and the influence of the loading rate is diminished.

It boils down to drop height. ■

OK, what is the load imposed by the largest lump,

Roark, what would we do without him. ■

The most signifcant force during loading rail cars is the loading mechanism (logic controlling flow gate and bin configurations) above the raiil car. Once you open the gate, a stream is accelerated to impact the bottom of the RR car. The maximum pressure is reach just before midway during a loading cycle. The logic must anticipate the rate of loading given by the load cells and knowing the bin and gate influence on the granular dynamics. This is due to the material acceleration reaching a maximum reflected, by the pressure gradient about mid cycle.

I do not see the size of lump having a strong influence on this force, since the local lump force is spread over many particles in the bed already established. A large lump's greatest influence will be at the onset of loading as noted in a prior posting. Later in the loading cycle, I would guess the reverse is true due the inertia effects of many lumps stalling the action of one lump.

We can mimic this with our DEM code "Rocky". ■

Why do what should have already been done?

The company that manufactured the rail car would have had set parameters to which to design to. Just contact the manufacturer and request this information. If the manufacturer does not want to disclose this, then advise your client and request this information from them.

If the rail car manufacturer says it is is say -50 mm and you want to load -300 mm, then you are going to have to carry insurance should the rail cars be damaged. If you stay with the lump size that the manufacturer recommends, then it is their issue.

Of course it is more than just the lump size, but the lump mass and lump energy as well. ■

Originally Posted by designer

OK, what is the load imposed by the largest lump,

Roark, what would we do without him.

There is also a comprehensive calculation method given in the Sandvik Alloy Steels Handbook (or something like that) relating to dumper body design. I'd have to go back 33 years to get the exact title. Life's getting too short for repetitive research. ■

From first principles I might have

equated the kinetic energy of the lump to the 'spring' energy of the plate impacted

worked out the load deflection of the plate

established a 'spring rate'

used this to establish a deflection

used the deflection to establish a stress

But I'm old, so let some bright young thing do an FEM (or DEM) on a computer rather than me scratch away on a few bits of A4 paper!! ■

I've read your post,and I think we are the same at the packaging,normally the bulk bag is a good choice,maybe it is available for you.Our products:corn starch,corn gluten meal,maltodextrin,dextrose monohydrate. ■