Thursday, November 3, 2016

Open-car loads: weight

In this post, I discuss the weight of open-top car loads. I don’t mean added weight for modeling purposes, to bring a removable load up to a desired total car weight of the model. (I discussed that kind of weight addition in a recent post, which is at: . Instead, I mean recognizing the weight that a load would have as a prototype load. I have seen some model loads which clearly exceeded the weight capacity of the cars in which contained them. I mentioned that aspect with respect to my own modeling of chromite ore, and included information about the density of that ore (see that post at this link: ).
     Incidentally, I have written a number of posts about open-car loads over the years, and there are more than would be reasonable to list here. You can readily find them all by using the search box above and to the right of this text, with the search term “open-car loads.”
     One good example of a load requiring care with weight awareness is the load of steel bar I purchased at the 2016 Chicagoland RPM meet, just concluded (meeting summary at: ). The load was sold by Mark Caposieno, and here is a photo of it. I like the look of this load, because the bar ends look like hot-sheared bar stock, and are color coded on the end to designate whatever alloy they are, something you can see in the supply area of any machine shop.

There are 16 bars in this load, and the bars are about 23 or 23.5 scale feet long. Their diameter, in HO scale, is 11.3 inches. It’s then a simple matter to compute the volume, in HO scale, of each bar at about 16 cubic feet, which makes the entire load about 261 cubic feet. Steel weighs 480 pounds per cubic foot, so this load, though compact, would weigh over 126,000 pounds. This is close to the load limit on a 50-ton gondola, so even a 52-foot car of that capacity could only carry one of these loads. In many cases, a railroad would probably prefer to put this load in a 70-ton gondola if available.
     Here is this load in a 70-ton gondola, a Pennsylvania G22 gondola, in a mainline train on my layout.

I have sometimes been asked where one gets data like weights per cubic foot (of anything). Just Google it, and Wikipedia or other source will deliver.
     Another example of this weight topic would be a load of car wheels. As I described in some detail in my article in Model Railroad Hobbyist for September 2016, wheels like this weighed about 850 pounds (you can download this or any MRH article for free, any time, from their website at ). I have used old plastic wheels and glued them together with contact cement, then painted them rusty, so that they look like this:

This load is a single layer of wheels, which fits into a 40-foot gondola. It contains 53 wheels. which amounts to 45,000 pounds. That is well below the capacity of a 50-ton gondola, but a load I saw once on someone’s layout, of a gondola filled to the top with wheels, would considerably exceed the capacity of a prototype car.
     Shown below is this load on my layout, arriving at the shop attached to the roundhouse in Shumala. The fairly uniform rust color and lack of dark, oily dirt on wheel faces means that these are new wheels to be used as replacements.

     One might object that after all, these are model loads and do not themselves weigh very much in most cases. But I want loads in my open-top cars to reflect the same realities as anything else on the layout. Model loads should reflect the look and size that a real load would have to have.
Tony Thompson

No comments:

Post a Comment