Tunnel works on the outbound tunnel towards Dhoby Ghaut are slated to begin later this month, with the Land Transport Authority saying the project is progressing as planned. SINGAPORE: Tunnel strengthening works on the Circle Line (CCL) have reached the halfway mark, with the Land Transport Authority (LTA) confirming on Tuesday (Feb 10) that the project remains on schedule for completion by April. The scheduled service disruption , which began on Jan 17 and runs until Apr 19, has seen trains