Riding the Metro

I ride the Metro (subway train) everyday to get to work.  It takes about 45 minutes each way.  Tuesday morning I was later than I like to leave.  As I rode the escalator down to the Metro, the train just arrived, so I hurried to get on before it pulled out.  As usual, I started reading.  After awhile, I heard the conductor say Rosslyn stop.  My stop is about four stops later, so I continued reading.  Suddenly, the train popped up above ground!  The sun was shining.  My train stays underground all the way to my stop.  I am on the wrong train!!  I am on the way to the airport.  I get off at the next stop and catch the next train going the other way.  I have to ride it until it gets to a transfer stop so that I can get on the correct train and then ride to work.  A strong reminder to pay more attention when getting on the train.