Best discharging points of railway transport tanks for aggresive chemicals; acid?

Question

best option to discharge aggresive chemicals specifically acid from railway transport tanks, is it in the bottom or at the top, please cite advantages and dis-advantages

Answer 1

Look to the manufacturers of the railway tankers. I researched r/w tankers and cars a few years ago and each manufacturer has a web site with pictures and descriptions of each type unit. Usually there is a telephone number, or web link, and  you may call or email them direct. They are most helpful as a general rule ,when you ask for specifics.

...jj

Answer 2

Most tank cars are unloaded from valves underneath the cars.  In the case of acid or other chemicals that are corrosive to metal, the cars are glass lined to keep the material from coming into contact with the steel of the car.

In other instances they are unloaded from the top, such as cars carrying LPG.  The dome on the top is referred to by many as a "manhole", but in actuality it contains the necessary valves and isn't an access hatch at all (except for heavy maintenance).

Other tanks carrying bulk liquids are unloaded from the top as well through simple siphoning devices.  A good example are those cars carrying diesel fuel for locos, and at many servicing facilities the fuel is pumped directly from tank car to fuel tank of the loco.

The advantages are simple.  If unloading corrosives from below, no spillage will run down the side of the car eating away at the metal, with air intake at the top, letting gravity do the work of otherwise necessary pumping mechanisms.

As for unloading from the top is concerned, it is more convenient, therefore less dangerous, requires little underground piping and reduces the chances for a spill.

Good question.  Good luck.