The scenery part of the fixed track (only arrows shown in surveyor) is copied but not the track (spline object) part of it so it's not an option. At least that's how it works in TRS2004.
Not all scenery objects are copied over with copy and paste either for instance tacksides are not even though they are scenery and stored in the obs fle.
Right now you'll need a 3rd party utility to copy and paste spline objects - track, roads, fences and the like. This is one reason why I started doing my route design work in cad so I could move, copy, rotate and/or translate any track arrgt I wanted at the drawing stage and then convert it directly into a trk file with the utility I wrote. It won't do a general copy/paste of splines. It will though take a specified part of a cad drawing and scale/translate/rotate and convert or optionally merge it into an existing trk file.
Bob Pearson