Proceeding of the Joint International Symposium on Deformatuon Monitoring. 2-4 November, 2011. Hong Kong. China. Report. Automatic Deformation Monitoring System (ADMS) has proven to be an effective method to determine the deformed objects in space by measuring their spatial coordinates periodically with minimal human intervention. To ensure the information acquired by the ADMS is true and accurate in producing a reliable report, detailed planning with an overview of the project requirement is necessary in order to come up with an optimal design of the system meeting the need of all concerned parties. The site constraint and the interest of stakeholders should be carefully reviewed and considered. The West Island Line (WIL) in Hong Kong is a railway project undertaken by MTR Corporation to extend the existing Island Line beneath the busy and densely populated areas in the western part of Hong Kong Island. The ADMS is installed to monitor the tunnels and the building structures during construction activities at different stages of the WIL. In this paper, the application of ADMS in the operating railway overrun tunnel will be discussed. The discussion will elaborate on the design of the survey reference network, defining an appropriate alarm system, incident reporting and analysis, and challenges of the constraints on site.