Railway Wagons: Bottom-discharge vs Tippler

Yep. The UK does it, among others.

In this part of Wisconsin there is a lot of "frac-sand" mining. It is all shipped in hopper bottom cars.

Why not explore the use of combinations of both systems? They could then be used anywhere.

Google: coal unloading from wagons

Coal is coming to an end on the railways of the UK anyway.

40+ years in quarrying and I’ve never come across anything other than bottom discharge. It’s far quicker and easier for bulk loads.

Well, for something new here's some scale models of the ubiquitous "Airfix" 16T mineral wagon. Over 100,000 were built:

The white stripe indicates which end the tipper-end-discharge-door is.

If your doing this for a personal project it is one thing,

If your doing this for pay, provide enough information to keep yourself a part of the solution.

I once read an article in model railroader that explained in detail the research you are working on

Yes - the question struck me immediately as a question from a model rail fan looking for a non-typical real world situation that would allow his use of the wrong type of car on his layout.

I am fairly sure that the Ma'aden Alumina Refinery & Mill used bottom discharge rail cars (it definitely uses rail cars). The rail line runs from the middle of Saudi desert - about 700km in a straight line.

The refinery is just north of Jubail shows up clearly on Google Earth

I work at a company that uses both types of unloaders, but for coal.

Thanks for all the responses! I'm only peripherally involved in this discussion at work, but remain curious re. things I don't know a lot about... The question on bottom-discharge/hopper vs rotary tippler discharge has quite few facets to consider. (One of the financial/operating considerations would be the capital outlay of cheaper gondola wagons with an expensive tippler, vs the more expensive bottom-discharge wagons with a cheaper off-loading facility, coupled with differences in maintenance costs & outages, wagon length, Gross/Nett ratio, axle loads, etc.)

I have seen enough examples of both systems in the coal world, but for heavier minerals (ores with an SG >2.5, say), tippler systems seem to dominate, even over shorter distances, with very few examples of bottom-discharge wagons over the longer distances sometimes seen in coal. My initial question was posed just to see if I'm missing something obvious. I've looked at some systems in Australia & Brazil to start off with.

(Sorry for being a bit cryptic, but I don't want you to do my work! And there are some sensitive issues that limits my ability to discuss in more detail )

The biggest advantage I see to unloading a car by rolling it upside down, is that it is difficult to clog. Draining through a hopper facilitated by a vibrator still requires intervention sometimes.

Gideon you may find some interesting information here. Bottom-Discharge.

sishen to saldanha railway line.

The Sishen–Saldanha railway line, also known as the Ore Export Line, is an 861-kilometre-long (535 mi) heavy-haul railway line in South Africa. It connects iron ore mines near Sishen in the Northern Cape with the port at Saldanha Bay in the Western Cape.