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Mexico City Metro For Lines 1–6, Metro control center employees without a functioning telemetry system rely on track monitors and calls from drivers to know where trains are located. CDMX Metro

A year after Metro fire, dominoes help monitor location of system’s trains

'We continue [to work] blindly, imagining where the train is moving forward'

Mexico City Metro employees are using dominoes to “imagine” the location of trains a year after a fire in the subway system’s downtown substation put train monitoring and communications systems out of action.

The operation and supervision of Lines 1, 2, 3, 4, 5 and 6 of the Metro system is “literally a board game,” the newspaper Milenio reported after visiting the subway system’s No. 2 Central Control Post (PCC2).

Metro employees known as regulators move dominoes on a paper map to simulate the movement of trains along those lines, the newspaper said. Train drivers notify regulators of their location via the WhatsApp messaging service.

One regulator conceded that “we can’t see the location of the trains in real time” before adding that train drivers “frequently call us to tell us where they are.”

“That’s when you put the domino in its place,” the employee said, adding that regulators use their imagination to determine the exact location of a train.

2019 fire at CDMX Metro system management station
Emergency crews responding to the fire at the Metro’s PCC 1 control center on January 9, 2021. Twitter

Before they started using dominoes, the Metro workers used items such as erasers and pencils to depict trains, Milenio said.

“They later progressed to a domino system. Due to the loss of the internal Metro communications system, Tetra, they [train drivers and regulators] had to use the WhatsApp application to communicate … [despite] the risk that there are spaces in the Metro that don’t have [cell phone] service,” the newspaper said.

The introduction of dominoes is not the only “improvement” that has been made to the rudimentary train monitoring system.

Regulators previously used paper boards with hand-drawn representations of the Metro system, but they now use maps downloaded from the internet, which show the different lines in different colors as well as the location and names of stations.

The latter are “a little clearer,” said the employee who spoke with Milenio. Asked whether it was safe to operate the Metro with such a monitoring system — which was only recently enhanced by the installation of monitors that transmit footage from the subway’s lines — the regulator responded:

“… With dominoes or erasers, we continue [to work] blindly, imagining where the train is moving forward. … We assume that [the trains] are [at a certain location], but we don’t have the visualization. They [the drivers] tell you they’re between stations, but you don’t know where. … It’s not precise at all, but you imagine [where the train is], put the domino down and assume that it’s there.”

CDMX Line 12 Metro collapse
The Metro workers union says members work with rudimentary equipment while trying to avoid another incident like the collapse of an overpass on Line 12 last May. Government of Mexico

Due to the lack of precision, the number of trains running on Lines 1, 2 and 3 is now lower than it was before the substation fire on January 9, 2021, the employee said.

“Lines 4, 5 and 6 are operating normally; they’re relatively small lines. But the circulation [of trains] on the large lines … is 30% lower,” the regulator said.

The employee also said that the PCC2 is short-staffed due to coronavirus infections among its personnel.

“There are currently nine colleagues with COVID, and we’re working double shifts. There are times at which we don’t have support on the large lines … [and just] one supervisor controls the … [monitoring system]. … When a problem arises, communication [with drivers] takes a lot of time, … you have to call each one to notify them of the problem, and that’s very complicated for just one person who is controlling everything,” the regulator said.

The Metro workers union acknowledged in a statement that its members are working with rudimentary equipment while trying to avoid “another serious incident” on the subway system. Twenty-six people were killed last May after two carriages of the train in which they were traveling plunged toward a busy road due to the collapse of an overpass on Line 12.

The Metro workers union said that the lack of sophisticated monitoring and communications systems is “putting [drivers’] instincts to the test,” forcing them to rely on “the experience they have acquired in their years of service.”

It also said that the administration of the Metro system by former chief Florencia Serranía was “disastrous.”

She was replaced by last June Guillermo Calderón Aguilera, a veteran transport official but the primitive monitoring system survived the change of leadership.

The newspaper Reforma reported last May that a domino system was in place because the subway’s digital telemetry system hadn’t been repaired. The “Monopoly” system, as one Metro employee described it, was ridiculed by Reforma readers, with one calling it a “true embarrassment” and another describing it as criminal.

“Only in Mexico!” wrote one person. “Great Mexican technology,” another said ironically.

With reports from Milenio and Reforma 

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