(Portland, OR)  --  Flooding on the tracks has prompted Amtrak service to be suspended between Portland and Vancouver.  An Amtrak spokeswoman told "The Oregonian" that the BNSF Railway has closed its tracks north of Union Station in Portland until the water recedes.  Officials say passengers on Amtrak's Cascades trains are being taken by bus between Portland and Vancouver.  Coast Starlight and Empire Builder trains are being rerouted over Union Pacific Railroad tracks.