WORK to stabilise cliffs above the railway on the California coastline at San Clemente, south of Los Angeles, has suffered further delay, as contractors work to ensure that the installation of ground anchors does not damage the foundations of neighbouring buildings.

The route between Laguna Niguel/Mission Viejo and Oceanside remains closed. Amtrak and Metrolink commuter services having suspended operation in October 2022 following concerns over landslips on a 213.36m-long slope above the main line between Los Angeles and San Diego.

Train services are not expected to be restored until late March. Original estimates were for the route to reopen at the end of 2022, later pushed back to February 2023 after a previous spell of heavy rainfall.

Amtrak and Metrolink suspended operation after geologists raised concerns over a 71.2cm shift in the alignment between September 2021 and September 2022 following repeated storm damage to the coastline. This resulted in erosion of the shoreline below the track, and movement of ground above the railway, particularly a slope between the line and a housing development on the clifftop.

Since November 2022 the Orange County Transportation Authority (OCTA) has been working with geotechnical contractor Condon-Johnson & Associates (CJ&A) to perform emergency stabilisation work.

CJ&A has been installing two rows of ground anchors driven deep into the bedrock along the slope above the line, but OCTA says the contractor must now adjust its approach to installing several anchors at the south end of the project to ensure existing foundation piles are not disturbed.

“Once work got underway, it was determined that the existing plans for the homes were not precise in detailing the location of the piles,” says OCTA spokesman, Mr Eric Carpenter. “Because of this, it required some changes to how the work would proceed to ensure safety, prevent additional movement in the hillside, and avoid any damage to those existing piles and the homes above.”

Carpenter says that the first row of anchors has been installed and that no further movement in the slope has been noted.

OCTA has added boulders to fortify the rock revetment along the beach and in December proposed that protection of the main line to San Diego should be improved by building more boulder seawalls along the 11km stretch of coast between San Clemente and Dana point.

“Like everyone who travels this critical link in the state’s rail network, we want to see this emergency work completed as quickly as possible, but at the same time we have to be certain that trains are running on stable tracks and passenger safety is never compromised,” Carpenter says.