On Sunday, May 25, Monday, May 26 and Tuesday, May 27, the Sheppard subway will shut down at 11 p.m. in order for scheduled maintenance to take place. From 11 p.m. until 2 a.m., frequent express shuttle buses will run between Sheppard-Yonge station and Don Mills, stopping at Bayview, Bessarion and Leslie. This online document gives you more details.