Re: tank capacity

Jeff Coleman

--- In STMFC@..., "ed_mines" <ed_mines@y...> wrote:
I'm a chemical engineer and a chemist by profession.

Filling a tank with liquid to meassure the actual capacity is an
proposition, particularly if it's a large tank. It takes a long
to fill and the accuracy of the metering device is questionable.
(Years ago I used something called a Neptune meter a couple of
it looks like a mechanical gasoline pump.)Calibrating the metering
device is difficult.

But if you can weigh a tank full of water and empty it it's pretty
easy to calculate the volume of the tank. Water weighs 8.34 lb/gal.
An 8000 gallon tank car would hold about 66,720 lb. of water (33.36

The only problem might be that a steel tank could be prone to rust.

Getting rid of the water is easy. Pump it into the next car. If you
did that with a given volume you would have no idea how much is
to eulage (the amount that doesn't want to come out of a container).

Ed Mines

I'm a tank car inspector. I'm not sure how the car builders
calculate the capacity of the tanks. I do know that the capacity does
vary from car to car of cars of the same lot and builder. Also you
are correct that steel tanks will rust. But all tank cars up untill a
couple of years ago were filled with water and "TANK TESTED". The car
was filled with water and presserized to the tanks rated pressure.
This was done periodically, usually every ten years. The test date
and due date is stenciled under the car class, lefthand corner. To
keep the tanks from rusting many companies would purge the tank with

Jeff Coleman

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