Could be useful since empty

Here's the details

Let me start by saying if you're a rivet counter or at least like a super prototypical look to your rolling stock this may not be your cup of tea.

I've been in this hobby a long time and I know that even the best laid track will occasionally get derailments for no other reason than it might be Tuesday. Since the days of the old 'Mantua Heavyweights' I've noticed that overweighting freight cars helps keep them on the track. Plus as an added bonus, it gives the the train a more realistic feeling when you need to notch up the engine(s) a little to overcome the resistance of the extra weight. 

I do like to keep my railroad looking as realistic as possible (although I am still mostly a 'plywood pacific'), but I am completely freelance so I do sometimes take a little artistic license. Such is the case with these hoppers as you'll see shortly.

As you can see, there are fairly light out of the box. I've started using the JoeF and Mike Confalone method of super weighting my freight cars. My boxcars are typically 8-10 ounces. My method with these hoppers is to simply glue pennies into the bays inside the car:

I was able to easily fit 6 groups of 8 inside the car. Initially I was just going to leave them like that but didn't like the way it looked so I decided to make covers out of black styrene:

I removed the inside braces to make it a simpler fit. Not 100% prototypical but I think it looks pretty good. And once I make the coal loads to sit on top you won't see it anyway. And the final weigh in:

2.4oz to 6.8oz. A 4.4oz increase. Still a little lighter than I like but I'm weighing the coal loads as well so I'll be well over 8oz by the time I'm done. So far I've done 10 of them the same way. They roll very nicely, haven't derailed yet, and only cost me 48 cents per car. Not bad for one afternoon's work. Now on to decals and coal loads...

Ah so nobody has harnessed

Ah so nobody has harnessed super dense metals from asteroids to allow us to overweight an empty coal car.  Dang, and those Arrowhead models have a close to prototypical look empty.

Still, good to know you can hide about 48 cents in pennies under a load!