If the left train is facing right and the right train is facing left.
return train  ;return #1 that is on the  left  ;return #1 that is on the  right  ;return if  #2 is facing right  ;return if  #3 is facing left  ;return if  both  #4 and #5 is true
['select', 'filter', 'filter', 'boolean', 'boolean', 'boolean']