% ruby sim.rb simulate pub3.in 
Train Red 1 entering Glenmont
Ann boarding train Red 1 at Glenmont
Train Red 1 leaving Glenmont
Train Red 1 entering Silver Spring
Amy boarding train Red 1 at Silver Spring
Train Red 1 leaving Silver Spring
Train Red 1 entering Union Station
Art boarding train Red 1 at Union Station
Train Red 1 leaving Union Station
Train Red 1 entering Bethesda
Aaron boarding train Red 1 at Bethesda
Amy leaving train Red 1 at Bethesda
Ann leaving train Red 1 at Bethesda
Train Red 1 leaving Bethesda
Train Red 1 entering Shady Grove
Train Red 1 leaving Shady Grove
Train Red 1 entering Bethesda
Train Red 1 leaving Bethesda
Train Red 1 entering Union Station
Train Red 1 leaving Union Station
Train Red 1 entering Silver Spring
Art leaving train Red 1 at Silver Spring
Train Red 1 leaving Silver Spring
Train Red 1 entering Glenmont
Aaron leaving train Red 1 at Glenmont