The Palmdale to Burbank section will be the first to be developed on the San Francisco – Los Angeles high-speed rail line, the first high-speed rail system under construction in the United States, which will connect San Francisco, Sacramento, Los Angeles and San Diego on a total route of 1,287 km with 24 stations for travellers.
Technical challenges include those related to the seismic design of tunnels and structures. In particular, the tunnel and also surface crossing of active faults is a unique aspect, as is the tunnel design to withstand water pressures greater than 25 bar.
The tunnels are designed with different diameters to accommodate potential routing readjustments capable of absorbing the expected seismic displacements.
This first section of work has 45 kilometres of tunnel, including two tunnels with a length of more than 20 kilometres in seismic zones, crossing faults including San Andrés, San Gabriel and Sierra Madre.
The overall project includes the execution of 6 deep surveys (down to 900 m) for investigation of the base tunnels. A specific study has also been developed for the tunnel ventilation system.
It will also incorporate state-of-the-art traffic signalling and safety technology, such as positive train control (PTC), anti-intrusion barriers and an early earthquake warning system, among other developments.