CN sold the Alexandria Sub to VIA in June 1998 between Mile 7.5 De Beaujeu and Mile 72.5 Hawthorne......4 miles from the Ottawa Station. The CTC system had been extensively damaged in the Ice Storm of that year and since the line now carried mostly VIA traffic, it just wasn’t cost effective for CN to invest in new infrastructure.
VIA rebuilt the line, adding passing siding and a new signalling system which has allowed an increase in speeds.
An interesting recent move is the through-routing of Montreal <> Ottawa <> Toronto trains......They now continue on through the Ottawa Station after a brief stop with passengers just staying aboard. Wonder if this will eventually lead to the reinstatement of the overnight train via Ottawa.......something VIA had planned to do when they launched the “Enterprise” in 2000. This route would serve more passengers and just about use up the extra time the train just sat and waited in the Kingston Yard before continuing on.