(Portland, OR)  --  TriMet is warning commuters to brace for longer wait times this week as temperatures rise amid an excessive heat warning.  TriMet officials say that MAX trains are required to run ten miles per hour slower than normal when the temperature rises past 90 degrees.  The trains will slow down even further to 35 miles per hour if the thermostat hits triple digits.  Meanwhile, the WES commuter train will stop running entirely if the thermostat reaches 105 degrees.