Santiago pins its hopes on metro line No. 7

In her final state of the nation address, Chile's President Michelle Bachelet announced that her government is committed to financing the seventh line of the Santiago subway system, which is expected to cost US$2.9bn.

The announcement came after the initiative was stuck in the feasibility phase for nearly three years.

LINE 7

The 24.8km metro line No. 7 will have 21 stations in seven districts of the Chilean capital, and is expected to be finished by 2025.

The line will run from the eastern Vitacura district, which will have six stations, passing through Providencia (one station), downtown Santiago (three stations) and then the western districts of Quinta Normal (three stations), Cerro Navia (three stations) and Renca (three stations).

According to a statement by subway operator Metro de Santiago, the line is expected to benefit nearly 1.4mn residents.

CONGESTED LINE 1

Franco Basso, an industrial engineering professor at Diego Portales University (UDP) in Santiago told BNamericas that the main benefit of the line is that a long section of it will run parallel to the overcrowded line No. 1.

"Sometimes during rush hour, line 1 has passenger traffic that can reach 40,000 users per hour per direction." he said, adding that is the limit of the system's capacity.

Iván Poduje, an architect from Chile's Catholic University (UC) and partner of independent urbanism office Atisba, told BNamericas that line 1 receives nearly 40% of the network's total passengers. The subway system's four lines currently cover 100km.

Poduje says the situation could get more complicated in the short term due to the recent opening of the Rancagua-Nos express rail service.

He says the impact of the service on line 1 so far has been less than expected, but he adds that once the rail line is fully operational, "it will add an important amount of passengers to Estación Central station [line 1], which is already pretty saturated."

Basso says that on some sections of line 1, passenger density can reach up to six users per square meter.

The UDP academic also estimates that the upcoming opening of line No. 6 will complicate things further on line 1 because the new line ends at line 1's Los Leones station, bringing even more users onto the overcrowded service.

THE SOLUTION

Basso initial estimates indicate that line 7 could reduce passenger flows on line 1 by about 10,000 users per hour per direction. "At Metro, they say this equates to eight empty trains."

He expects the new line will be able to transport 25,000 passengers per hour per direction.

Meanwhile, Poduje estimates that the line needs to reduce line 1's traffic by about 10% in order to make the change noticeable, although he also says that "we need line 7 to be operational in half the estimated time."

Basso adds that the benefits of line 7 are not just fewer passenger numbers on line 1, but also the opportunities it creates to expand the network even further.

"A parallel stretch to line 1 will allow analyzing projects for other lines that aren't possible today. For example, one stretch proposed by both presidents [Ricardo] Lagos and [Sebastián] Piñera is the Florida-Macul line, which is currently unfeasible without line 7" due to the overcrowding on line 1, he says.

Basso also says line 7 could help improve train frequencies on other lines.

"Currently, line 4 operates at 70% of its normal speed," he says, which he attributes to overcrowding at Tobalaba station, which is a transfer point to line 1.

Poduje says there's also a chance to extend line 7 even further west to Santiago's airport. However, he adds that "there are other sectors that need the metro before that," pointing out that the line will improve urban development in districts currently not on the subway network like Cerro Navia, Renca and Vitacura.