Traffic Lab is a Seattle Times project that digs into the region’s transportation issues to explore the policies and politics that determine how we get around and how billions of dollars in public money are spent. Don’t cancel our train lines. That was the dominant message Thursday from residents who filled Sound Transit’s boardroom, to insist the giant agency keep its 2016 campaign promises to reach Ballard, Issaquah, Tacoma, Everett, West Seattle, and other new destinations, despite a $35 billion funding gap. The latest light rail project list , published this week, would cut or postpone several stations until some unknown year, when more money or cost savings might be found. At least in the near-term, the network will be less than what voters expected when they approved higher sales, car-tab and property taxes for the ST3 plan.…