Which crossing is it exactly, because millerhill depot being out of wack would suggest it's somewhere at Niddrie south junction, which wouldn't impact the main ECML. They are also running from Millerhill depot through Craigentinny and into Waverley as I send this, with 5R81 making the trip.
The main ECML single line working suggests it's either the points at Portobello Junction between the Leith Docks Branch and the up main, or Craigentinny junction where the old Powderhall Branch also joins the up main (which I thought had already been plain lined)