The application was discussed somewhere upthread when open for consultation, and was mainly about bridges and level crossings. Its website is
here. I don't think there was anything about extra tracks.
The main application for a TWAO is yet to come and according to the page I've just linked will be submitted this summer.
An intriguing element for which we have not yet seen details is "reconstruction" of the viaduct at Kirkgate and Marsh Lane, Leeds. Presumably that's for structural condition, not extra tracks.