Zweisystem was in Portland during the 2007 ice storm and what an experience. Portland’s car drivers seemed ill equipped to deal with ice and tried to drive like it was snow and the following video shows the results.
The following video shows a four car MAX train clearing the ice build up in the flange way at an intersection. The build up of ice in the flange way breaks the electrical contact and stops the train, thus a four car train is needed to clear the flange way so at least one vehicle remains in the electrical circuit. Portland up to 2008 did not invest in snow and ice removal vehicles, unlike other cities who operate light rail in harsh winter conditions and removal of snow and especially ice is done manually.
Just a note: Vancouver hasn’t endured the ices storms that Portland now seems to get on an almost regular basis and when the last time an ice storm hit Vancouver in the late 90’s, the ice build up on the SkyTrain reaction rail stopped the SkyTrain metro system.