In fact in the SCR TT proposal for 2019, a 3 hour speed up was proposed in exactly this stretch (screenshot attached) . So dont think the issue is there from their end (SCR). I think CR might be a blocker here. If implemented, then probably against its current arrival time at 4am, it may end up reaching at 1am or midnight....not sure if that is an issue. This is the only train that has been given this much time in this stretch