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A30 world news
Diabierna 18 Juni 2021

Report blames poor welds for Mexico City subway collapse

(AP) — A preliminary way line was designed and
report by experts into built.
the collapse of a Mexi-
co City elevated subway Experts said unusually sharp
line that killed 26 people curves in the route exac-
placed much of the blame erbated problems with the
Wednesday on poor welds wheels-on-steel track design,
in studs that joined steel which more resembles New
support beams to a con- York’s subway rather than the
crete layer supporting the European-style rubber tires
track bed. used on the rest of the sys-
tem.
The city government hired
Norwegian certification firm The Gold Line line chattered,
DNV to study the possible bumped and shrieked. The
causes of the May 3 acci- rails began to take on a wavy
dent, in which a span of the pattern. Drivers had to slow
elevated line buckled to the trains to as little as 3 mph (5
ground, dragging down two kph) on some stretches.
subway cars.
In 2014, the Gold Line had
The report also said there to be shut down for months
were apparently not enough for the tracks to be replaced
studs, and the concrete or ground into shape.
poured over them may have
been defective; the welds Ballast was added between
between stretches of steel the train’s tracks during those
beams also appear to have ing upward from the beams company owned by telecom design flaws, corruption and repairs, and some say extra
been badly done. were covered with a poured and construction magnate conflicts of interest. weight and possible poor
concrete slab meant to help Carlos Slim, currently Mexi- maintenance could have been
“The studs showed deficien- carry the weight. co’s richest man and once the A top executive of one of the potential factors in the col-
cies in the welding process,” world’s wealthiest. Slim is an companies that built it was lapse.
the report states. But the studs were found to engineer by training and his the brother of the man who
be still carrying ceramic rings firms are currently involved oversaw the project for the An official 2017 survey of
The existence of construction that covered the welds. Used in building some parts of government. damage from a deadly 7.1
defects when the line was as a safety and control method the controversial Maya Train magnitude quake showed in-
built between 2010 and 2012 to contain the molten steel, project, which will circle the The scandal over forced clo- dications of construction de-
could be a major blow to the the rings were supposed to Yucatan Peninsula. sure of the costly new line in fects. Authorities decided on
political career of Mexico’s have been knocked off after 2014 — just 17 months after quick patches, welding props
top diplomat, who was mayor welding so inspectors could Any suggestions his firm did it was inaugurated — essen- under the bowed beams and
at the time, and to Mexico’s see the welds themselves. shoddy work on the subway tially forced Ebrard into po- reopening service.
richest man, whose company The fact they were left in would be a serious blow to litical exile. He was rescued
built part of the subway line. place may suggest the welds his reputation as a sort of el- by his patron, new President Ebrard has argued that subse-
were not properly inspected. der statesman of the Mexican Andrés Manuel López Ob- quent investigations showed
The report centered on pho- business community. rador, who had helped make the line was judged to com-
tos and physical inspection That would fit in with reports him mayor in 2006 and re- ply with standards when it
that showed that metal studs that the project was rushed to The $1.3 billion Number 12 suscitated him by naming was built. He wrote that “the
welded to the top of steel completion so the Number Line, the newest section of a him foreign relations secre- supervision and maintenance
support beams had broken or 12 subway line could be in- vast subway system opened tary in 2018. that was up to the adminis-
sheered off cleanly, suggest- augurated by current Foreign in 1969, was ill-fated from tration that succeeded mine
ing the welds were defective. Relations Secretary Marcelo the start. The so-called Gold Despite the subway scandal, remains in large part an un-
Ebrard before he left office as Line cost half again as much Ebrard was put in charge of known.”
The beams could not carry mayor in 2012. as projected, suffered repeat- Mexico’s efforts to obtain
the weight of the track bed on ed construction delays and coronavirus vaccines and was Following earlier investiga-
their own. The studs project- The section was built by a was hit with allegations of once considered a top con- tions into the design and
tender to succeed López Ob- corruption, more than 38
rador in 2024. government employees were
hit with fines or other pun-
Ebrard has said he’ll cooper- ishments for improperly
ate with investigations into contracting out work on the
last month’s accident. In a train, as well as some crimi-
statement Wednesday, he said nal charges.
the subway line was planned,
designed and built with help Since the May accident,
from “the best of Mexican much of the line has been
engineers.” closed. The elevated portion
of the tracks rise about 16
“Identifying the causes of the feet (5 meters) above a me-
accident is a necessary step in dian strip and roadway in the
achieving justice for the vic- poor southern borough of
tims of the tragedy,” Ebrard Tlahuac. Slender, reinforced
wrote. concrete columns are topped
by horizontal steel beams,
But previous reports by en- which in turn support pre-
gineering firms revealed Eb- fabricated concrete track beds
rard’s city government had on which gravel, railway ties
made a series of startlingly and tracks are laid.
wrong choices when the sub-