Would a Offset Ballast Hopper be used to transport gravel by rail or would a coal hopper be used ? thanks
A coal hopper could be used, but the slope sheet angle really is different for a freight car loaded with gravel. By ‘offset ballast hopper’, I assume you are talking about the Atlas or Athearn/MDC models. They are set up for dumping the ballast between and outside of the rails depending on how the gates are opened. A standard coal hopper will just dump the contents all over the track.
Coal can weigh anywhere from 69-94 lbs/cubic ft. Gravel can weight anywhere from 95-125 lbs/cubic ft, depending if it is dry or wet. Granite used in railroad ballast can weigh anywhere from 100-150 lbs/cubic ft(depending on the size of the ballast). This is why ballast hoppers many times have a white ‘do not load above this line’ marking on the side of the car body. I remember talking to a Soo Line trainmaster once. He mentioned that a ballast quarry overloaded a 100 ton capacity car to the max - he estimated 130 tons of product were in the car, and the rails at the loader were deformed. It took a front-end loader to remove enough ballast so they could even get the car over the scale track.
Jim
Thanks I was talking about them ,but If the gravel is load at a quarry and then ship to its destination is off of the railroad is it hauled by offset ballast hopper or not ?
A ballast hopper is generally used for ballasting track due to the manner in which it can dump its load. If you merely want to ship gravel from a quarry to a dealer or a concrete plant, a regular hopper car would be used. It could have offset or ribbed sides and, as mentioned, would not be loaded to the car’s full cubic capacity due to the density of the gravel.
Wayne
The dealer may also have a pit and a auger/conveyor, whereby the regular hopper dumps the gravel in a pit that lies in between the rails.
The Athearn/MDC 3 bay hopper would work for this, as well as the Walthers 100 ton gravel hopper or Ortner hopper (google search for pictures).
I’ve also seen gravel transported by regular gondola, where it is unloaded by a bucket crawler that travels along a berm next to the gondola(s) for some elevation. I’ve also seen pictures of a crawler using ramps to crawl onto the sides of the gondola and lower the bucket to unload the gravel. Some skillful driving there.
The type of car that’s used could depend upon whether or not it is a large volume business or a smaller less frequent user.
The problem with your question is an offset hopper is a coal hopper. So the answer is yes either way.
They hauled gravel in hoppers (which can be just about any type of hopper) most which could also haul coal and one of those types of hoppers is an offset hopper.
The real answer is they haul gravel in mostly twin hoppers because it is heavier than coal. Most offset twin hoppers were built in the 1930’s and were 50-55 ton cars. They could not be loaded to full cubic capacity because the rock was denser/heavier than coal. So that means offset cars would be used in gravel service up to about the 1970’s or 1980’s, after which the cars would be too old. Other types of hoppers could be used too but they couldn’t be loaded to full cubic capacity.
Modern gravel operations use twin hoppers, shorter Ortner style hoppers, gons, or ore jennies. Virtually all of those cars will have a 90-100 ton capacity.
Railroads can and did dump ballast or gravel from coal hoppers if need arises. Rig block and tackle to the hopper(s) door latch to regulate flow and chain a new tie in front of first wheel trailing where product is dumped to spread material no higher than top of rail. It’s not as neat or precise as a ballast car but you got to work with whatever type of car shows up.
Dick Haave
Hopper cars for ballasting Grand Canyon Railway’s tracks:
It is a matter of what you call the silicates you are hauling.
Rock is large. It can range from as small as cobbles (size of a human head) to over 200lbs per piece. This often hauled in steel gondolas though limestone cobbles and various ore cobbles were carried in wooden gons on the narrow gauge until the 1960’s
Ballast which is large stones often about ~2" in diameter can be hauled in any number of cars depending on whether it is simply going to market or going to be used right out of the car. Many were mentioned in previous posts in this thread.
Gravel which are very small stones ~1/2 - 3/4 inch is often transported in standard steel hoppers. Decorative or specialized gravel, especially sorted landscapers gravel is often bagged and shipped in box cars.
Richard