Through (and Through-US/DS) PID in globals will segfault due to something to do with having US and DS trackmatching tracks added to the through track- if these are not added (comment out lines 618 & 619 in Trackmatching.cc) then the Through PID works fine (but not Through-US or Through-DS as these look for the constituent tracks). The error isn't terribly useful- it complains about get_geometry_paths in BasePoint.cc, but clearly something within the global datastructure is getting messed up when the constituent tracks are added and then cloned - cloning is I believe the relevant issue as this problem does not occur when accessing through tracks in ReduceCppGlobalPID.

This is more a book-keeping type issue so that Jan can come back to it when other things are less pressing.