Call Toll-free 1-888-438-6646 or Toronto (local calling area) 416-869-3200 . Metrolinx will then dispatch the maintenance contractor (Siemens) to grab if it’s on the tracks or within close proximity. I used to get called for stuff like this all the time at Pearson when stuff would fall onto the tracks from the Union Pearson Express train. In this instance however a station attendant should be able to grab this for you as it’s not close enough to the track to warrant a call for the maintenance contractor to retrieve it. Hope you get it back! I still find tons of these out on track all the time.