What is Co-located CIQ Facilities?

Co-located CIQ facilities is an arrangement of Customs, Immigration and Quarantine facilities made in such a way that the travelling experience can be better for the users.
For example, in the upcoming KL – Singapore High Speed Rail (KL-SG HSR) project, travellers can expect to clear customs and immigration for both countries (Malaysia and Singapore) at their departure station. This will enable seamless travel experience as travellers can disembark from their train without further customs and immigration check at the destination station.
Source: The Straits Times