Metro Line 7

The Basic Engineering project of Line 7 of the Santiago de Chile Metro was approved in 2017; its Environmental Impact Assessment (EIA) was submitted for evaluation in 2019 and was approved in 2021.

The project design focused on trains with autonomous driving, platform doors and catenary power (on the train), similar to the already existing Lines 3 and 6. WSP actively participated in both the engineering and the socio-environmental planning of this great project, and contributed its international experience to this initiative.

This new line will connect seven communes in Santiago, and will integrate three communes for the first time into the Metro network (Renca, Cerro Navia and Vitacura). This will help alleviate public congestion on Line 1 and reduce travel times between from one end of the city to the other by more than half, thereby contributing to the democratization of the city.

The line has an approximate extension of 26 km, and includes 19 stations, 2 terminals, 13 passing and 4 combination stations (two of them triple combination and two double combination). The route is completely underground, with an average distance of 1.4 km between stations. For its part, the civil works include the design of 17.5 km of tunnels between stations and 2.3 km of station tunnel. The construction will be carried out using the NATM method (traditional method) for 11.5 km, and the TBM (Tunnel Boring Method) for approximately 6 km.

It is estimated that this new line of the system will be inaugurated in 2028, and will cost approximately 2.528 million USD.

An engineering aspect that required special attention was materializing and optimizing a layout that would allow the implementation of future transportation lines and interference with pre-existing constructions. For this reason, some stations were located deeper than usual, solving the complexity of passenger access to lower levels of the stations through an exclusive vertical transportation system.

The surface also posed a significant challenge for the new line, since the area it crosses consists of a large number of properties of historical and heritage value. This required WSP's environmental team to carry out a detailed survey of this type of infrastructure. Additionally, since Line 7 is located in an urban area close to the old part of the city, there is a high potential for archaeological materials, for which numerous surveys were developed that allowed the characterization of the archaeological heritage that could potentially be affected.

WSP also carried out a series of land expropriation studies necessary for the execution of the project -- an aspect that will be key during the construction stage. An iconic point of the city through which this line will pass is the Forest Park, a natural meeting place within the city due to its central location and green areas. In this sector, an intense process of community relations was developed with various interest groups --neighbours, authorities, users, social and territorial organizations, among others. Moreover, there was a detailed survey of the vegetation, and proposals for mitigation and compensation measures. The WSP team carried out fieldwork in which participation and flexibility prevailed to accommodate these concerns. This approach made it possible to determine the impacts that effectively constituted a detriment to neighbours, and to integrate these considerations into the design in order to minimize and mitigate the impacts. WSP's experience in underground metro lines globally made it possible to execute a design and environmental management that promotes the construction of a high standard line in every sense.

Services provided:

• Design
• Architecture
• Structural Engineering
• Mechanical Engineering
• Electrical Engineering
• Environmental Impact Assessment
• NATM and TBM tunnels
• Construction method
• Programming and cost estimation