The new line is not used for any regular traffic till the commissioner permits. So all regular traffic will run through existing single line on scheduled path. CRS inspection of new line is not usually expected to disrupt operation of regular line.
The Operation of the regular line shall be disrupted only when some work is done on that line, like CRS inspection of Electrification (when commissioner will block that line & other trains shall require regulation/diversion), or any non interlocking works (when points & cables are mostly re-installed)