when save max file and open it again,the RailClone Objects turning into a empty mesh,Because RailClone will read the MAX file's data in Library,but in the library,those MAX files was created by a old version of 3ds max,so,I open each MAX file and save again by a new version which the RailClone was installed,now,there is no problem,it's so good!
sorry for my bad English,I hope you can read it.Thanks a lot!