TTC TR Entering Line 4 Tail Tracks From North Platform at Sheppard-Yonge Station

I was walking up to the Sheppard Subway platform at Sheppard-Yonge Station when I saw a TR (Trainset 6146-6145-6142-6141) sitting at the north platform of the station, if you didn't know this platform is never used for passenger loading/unloading and I have never seen a train there until now. After a few minutes the train honked it's horn and started heading into the tail tracks, so I quickly pulled my phone out to record this cool sighting. Hope you enjoy!!!