OpenMM does not give progress for minimization, just wait...
4way-GCGA.pdb ...
1 nm
Energy at Minima is -160747.504 kcal/mol
saved  4way-GCGA_min.pdb
Cmd: rna_minimize.py -sp 4way-GCGA.pdb
Execution time: 199:23:59.630  start: 07:20:30 end: 14:44:29  
DONE!