SELECT  DISTINCT astops.name FROM
  route a JOIN route b ON a.company=b.company AND a.num = b.num
              JOIN stops astops ON a.stop = astops.id
              JOIN stops bstops ON b.stop = bstops.id
WHERE astops.name = 'Craiglockhart' AND bstops.name IN (
  SELECT  aastops.name  FROM
    route aa JOIN route bb ON aa.company=bb.company
                                           AND aa.num = bb.num
                JOIN stops aastops ON aa.stop = aastops.id
                JOIN stops bbstops ON bb.stop = bbstops.id
  WHERE bbstops.name = 'Sighthill'
  )