Service Adjustments from Sept. 19-20 Started Sat Sep 19 Until Mon Sep 21 Today, GO buses replace UP Express trains for planned construction. GO replacement buses will run direct between Pearson Airport Terminal 1 and Union Station Bus Terminal. Service adjustments on Monday, Sept. 21: -Trains departing Pearson Airport Terminal 1 to Union Station, between 05:27 and 00:54, will arrive and depart 1 minute earlier than regularly scheduled. Select your station to plan your trip.