Irrespective of the route name, the gnd file is now called mapfile.gnd and you will need to give it that name.
Locate the route in CM, click to highlight, Ctrl+Shift+E will open a new window showing the contents of the route folder, drag the new gnd file into the window overwriting the original, close the window. The route should still be highlighted in the main CM list, Ctrl+M will commit it. If the route isn't still highlighted you will find it under the 'Open For Edit' tab...