[PRR-talk] How many shovels of iron ore does it take to fill an H-21?

[Drye, John]

How many shovels of iron ore does it take to fill an H-21?

Listers:

I'm planning an iron ore train for my 1956-era N scale PRR. The idea is
to replace the Bowser H-21 coal loads with the appropriate amount of
iron ore and add some interior detail above the load.

There is a commercial casting that fills up the bottom quarter of the
car. However, I have heard that the hopper was filled to capacity with a
big shovelful of ore over each truck. I think this amount could be
modeled with a lightweight material like Styrofoam or sponge, painted
and covered with ore-colored rock.

So, can someone suggest how much ore it takes to "fill" an H-21? 

Thanks,

John Drye