Signalling systems are important for railways in the world. It keeps the trains at a distance to prevent collisions. To provide better and safer railway traffic the signalling technology has been well developed over the past century. Communication Based Train control (CBTC) is a significant example in railway signalling and it allows the trains to raise their permitted operating speed compared to fixed blocks signalling. Recently MTR Corporation in Hong Kong has changed a new signalling system for the East Rail Line to provide a more frequent train service for the passengers. It is believed that exploring the new possibility and the idea of improving the signalling system is going to bring a fascinating travelling experience to the railway industry.