I saw a tank car the other day labeled “molten sulfur.” Granting, this was with about a 10 degree temperature outside, in the middle of a road train, in the middle of a rural area not close to any industry, standing in a siding.
Ok, clearly the sulfur would not have stayed molten because of the temperature. So does it just solidify in the tank car and then get reheated to get poured out or what?
Here is some information referencing Rail Transportation of Molten Sulphur:
http://www.sulphuric-acid.com/techmanual/Storage/trans_sulphur.htm
FTL: "…Train Transportation
Large quantities of molten sulphur are transported by rail. An insulated sulphur railcar loaded with 40 to 70 tonnes of sulphur at 135oC (275oF) will stay molten for 10 to 14 days even in cold climatic conditions. This is possible because of the solidification of a small amount of sulphur on the inner wall of the tank that effectively insulates the remainder of the tank contents. When the tank car arrives at the customer, the car is heated using steam to melt the small amount of solid sulphur on the inner walls before the tank car is unloaded…"
Trinity industries advertises in their information referencing the manufacture of tank cars specifically for molten sulphur service. They are an insulated shell and have provisions for re heating the product for unloading (steam heating lines is one method to re-liquify the product in the car).