Tom Birkett of Bartlesvill, OK, provided some insight on how this commodity was unloaded from tank cars, such as pictured in the earlier post.
So if you are going to model the scene you now have a basis for the details.
Except in the very hot portion of the summer, steam heat will be required. Many tank car products are unloaded with air which is more readily available than a pump that can handle hot asphalt.
Hook up a steam hose to the connection on the bottom of the car (sometimes the connections are on the ends of the cars), hook up a hose to the bottom outlet of the loaded car, hook up an air hose to the Vapor space at the top of the car (not much pressure required)
Open the valves and if the stuff is hot enough to liquefy, it will unload easily.
I managed the Phillips Petroleum fleet for about 20 years and although we didn't move asphalt by rail, we moved a LOT of sulphur and it works the same, but they both smell bad!