The section between Birchmount and Unionville GO will be paid for by development charges as Downtown Markham gets built out. Seeing as the traffic in that area is far from congested I don't really think there's any rush. I believe this is also supposed to be coordinated with updates to Unionville GO station that will be adding another platform and I believe shifting the platform north a bit to enhance VIVA rapidway connections. It's also unclear how the VIVA rapidway will interact with the Rail bridge, will it just take two of the existing lanes? Will the bridge be expanded, will they only have one bi-directional transit-only lane?