as per my knowledge and research over this, it is said that the doubling of this section shall match the DFC timeline. In easy words, by the time EDFC completes, this route section shall also be doubled from Rajpura-Bathinda. For doubling through Patiala, in some areas, IR might have to re-align the existing track. As I have seen there is an ample space for doubling, just need to re-align or re-lay the existing track at certain portions.