(
      (
      STATION [OPEN, CLOSE, PRED1, SUCC1] (A1, true)
      |||
      STATION [OPEN, CLOSE, PRED2, SUCC2] (A2, false)
      |||
      STATION [OPEN, CLOSE, PRED3, SUCC3] (A3, false)
      )
   |[PRED1, SUCC1, PRED2, SUCC2, PRED3, SUCC3]|
      (
      LINK [SUCC1, PRED2]
      |||
      LINK [SUCC2, PRED3]
      ||| 
      LINK [SUCC3, PRED1]
      )
   )