CN 148 (Chicago-Halifax) and 149 (Halifax-Chicago) have been renumbered to 122 and 123 (respectively) as of today. No word yet on whether they are renumbered all the way through, or just from Montreal east.
CN 122 used to be a Montreal to Moncton train, a "modular" (as required) train, and 123 was Moncton to Toronto. The last time I have CN 122 recorded was April 3, 2004 at Windsor Junction, with CN 2522 and 2675. The last CN 123 I recorded was April 20, 2002 with GCFX 6068 and CN 5330 leading 53 cars. There may have been some that were more recent that I did not hear about.
CN 148 at Milford, NS on October 26, 2002.
CN 149 at McGivney, NB on February 19, 2004.