April 9th is the normal departure route.
I read somewhere that they are cutting in a viaduct on the Newmarket Sub, so they would be using the Bala Sub, but didn't catch the days.
The whole deal with going west on departure and essentially wyeing the train at Snyder to get on the York Sub heading east to get back to Bala Sub is because the summer train is so long they have no way of turning it. They run it to the maintenance center at Mimico, then back it up for spotting into Union Station, then pull out going forward up the Newmarket Sub. Looking at the detailed locations on asm.transitdocs.com it looks like today they backed it up the Bala Sub to Doncaster and wyed it there. You can see the locations go from the Bala Sub to the York Sub for the wye move.
It isn't a Wednesday versus Sunday thing. It was a one time occurrence due to temporary closure of the Newmarket Sub.
