一趟 vs 一次、is there any difference? Under the entry 趟 my dictionary says:


  
  For round trip 
  For single train trip
  


Does this mean, when I see this word I must assume the speaker  went back and forth, except when he went by train, where I must assume a single trip? 

This startles me very much, since knowledge of the means of transportation would be required, in order to correctly interpret the sentence!

Does 趟 imply that the speaker is now away from the place in question? So, does:


  我去過北京兩趟。


mean I am not in Beijing? Is this a difference between 趟 and 次？
My English is not good. This answer translated by Google Translate.

Nowadays these two words are mixed and there is no serious mistake. But here are some explanations.

趟

趟 is generally used for round trips in a specified time. Example:


  我今天去了兩趟超市。
  
  I went to the supermarket twice today


I went and came back twice. Now I'm home.

次

次 emphasizes number of travels and your experience from the trip. Example:


  我去過两次北京。
  
  I went to Beijing twice.


I just want to tell you that I have that trip.