A stop sign at a railway crossing means you must come to a complete stop between:

• 5 - 10 metres from the nearest rail
• 5 - 15 metres from the nearest rail
  Explanation:

  "A stop sign at a railway crossing means drivers must come to a complete stop at a safe distance—between 5 metres (15 feet) and 15 metres (50 feet) from the nearest rail—to check for approaching trains before proceeding."
• 15 - 20 metres from the nearest rail
• 20 - 30 metres from the nearest rail