Engineering Services for Emergency Repairs

Most of us don’t think twice about the critical infrastructure that we depend on every day—highways and railroads, municipal pipelines, rock and soil slopes—but when the unexpected happens, it brings commerce and transportation to a stop. Blocked rail lines or highways and out-of-service pipelines inconvenience the public and result in lost revenue. Delve Underground has provided emergency engineering services and repairs for these types of situations for over a quarter of a century. Examples of emergency projects include railroad tunnel fires, portal structure collapses, and rock slope failures.

Our ability to respond quickly lies in our expertise in geotechnical and structural engineering, experience in construction management, specialized in-house unmanned aerial vehicle (UAV) operators and rope access teams. These solid qualifications enable us to provide flexible repair designs using readily available materials to meet the site conditions. Furthermore, Delve Underground’s decades-long working relationships and collaborative design approaches with both owners and contractors have given us deep knowledge and understanding of the tunnels, and their original designs and construction techniques. We have performed repairs in nonemergency situations, which makes us even better prepared to move quickly in emergency situations.

Railroad Tunnel Fires

Delve Underground has supported first-responder teams on emergency situations involving active railroad tunnel fires caused by wildfires and arson. These fires pose a significant threat, potentially damaging or destroying the original timber sets and lagging within the tunnel, leading to a loss of structural integrity and potential collapse of surrounding materials. Even in tunnels with concrete liners, fires can cause the embedded timber sets and lagging to burn, resulting in spalling of the concrete due to extreme heat. However, complete tunnel collapse is less likely in these instances due to the remaining concrete liner.

In one instance in Southern California, a train derailment ignited a fire inside a concrete-lined tunnel, which affected the embedded timber sets and packing behind the liner. Delve Underground was called on to give recommendations to first responders for fire suppression. Utilizing grout pumped through holes in the liner, we extinguished the fire behind the concrete. However, the intense heat caused spalling of the concrete liner. After the fire was extinguished, our team assessed the damage, offered repair design recommendations, and stationed engineers on site to ensure ongoing stability during the repairs.

Another railroad fire emergency occurred in July 2021 when a massive wildfire engulfed a 480-foot-long tunnel along an active rail line near Quincy, California. The tunnel’s liner consisted of timber sets, concrete panels, and steel sets; the fire caused the 190-foot-long section of timber sets to burn and collapse, blocking the rail line. Delve Underground promptly responded to the emergency, delivering a conceptual repair design and bid documents just five days after the tunnel collapsed. Through a competitive bidding process, a contractor was selected and mobilized to the site within two weeks. Despite challenges such as wildfires still burning, closed roads, and shortages of supplies nationwide, construction began before the fire was fully contained. Our team, along with the contractor, worked seven days a week until the tunnel was reopened. Remarkably, despite the remote location and adverse conditions, the tunnel reopened to freight traffic in October 2021—about 10 weeks after repairs commenced—with no recorded injuries.

Railroad Portal & Snowshed Structures

Railroad portals and snowshed structures often face considerable challenges from excessive rock and avalanche loads, exceeding their original design specifications. In November 2015, a timber snowshed outside of a tunnel that was erected in 1943 in the Cascade Mountains in Washington State was hit by rockfall and partially collapsed, obstructing train passage along a mainline track. Delve Underground swiftly responded to the emergency, evaluating the rock slope above the tunnel from where the rock had fallen and providing recommendations for temporary repairs that allowed trains to resume operations in less than 48 hours after the rockfall.

Subsequently, Delve Underground’s rope access team conducted thorough investigations to assess unstable areas of a 250-foot-tall rock slope above the snowshed. This assessment led to slope mitigation measures that included the installation of rock anchors and wire mesh, which was completed in 2018. However, in July 2019, during roof timber replacement, another rockslide occurred in a different location, damaging major timber elements and puncturing the snowshed roof. This posed a new threat to passing trains. Delve Underground acted promptly, evaluating the slope’s stability, allowing trains to cautiously pass through the area while contracting with a slope stabilization contractor to repair the slope. Our mitigation strategies evolved with the changing geomorphology of the site, leading to successful completion of the project in July 2020.

In a separate incident on Christmas Day 2020, a rockslide destroyed the wooden portal structure of a railroad tunnel in Wyoming’s Wind River Canyon. Delve Underground quickly assessed the situation, and used rope access and UAV imaging techniques to evaluate the extent of damage and develop repair plans. A specialized rock contractor, working with Delve Underground’s design for stabilization, removed unstable rocks from the overhanging slope and reinforced the slope with rock anchors and drains. Delve Underground designed a new steel portal to replace the damaged timber portal. The project was completed 1-1/2 years later, in June 2022.

Delve Underground’s expertise, experience, and specialized in-house teams have made us the go-to company for emergency response for railroads and government agencies.