Hello. How are you ? I teach English in a college, and you ? I could help you to improve your spoken English. It is free of charge. I just want to meet new friends and know their cultures, such as : interesting places, education, food etc. Please add me & talk on Skype directly = aliagil1

Hi Hatifnat, I think the only difference is context. 'General Rules For Freight Traffic' sounds more like an instruction - for example as a sign on a wall - 'General Rules of Freight Traffic' would be used in general discussion. Tricky question! I hope this makes sense but I'm sure someone will explain it better than me! Lee

"General rules of freight traffic," I suppose.