Mexico City Metro overpass collapse

The Sistema de Transporte Colectivo (STC) operates the Mexico City Metro,^[3] one of the world's busiest urban transportation systems, which served approximately 4.5 million passengers daily in 2019.^[4][5] Established in 1969, STC is the second-largest metro system in North America, following the New York City Subway, in the United States.^[6]

Before the collapse, there were reports of deterioration within the rail system, and concerns about its maintenance and operations were raised.^[7][8] In March 2020, two trains collided at Tacubaya metro station when one driver failed to follow parking protocols, leading to a brake failure.^[9] In January 2021, a fire in the Metro's downtown headquarters resulted in the death of a police officer, hospitalized 30 people, while taking six subway lines out of service for several days.^[6][10][11] In April, Line 4 was closed due to a fire on the tracks.^[12]

In December 2018, the recently appointed head of government of Mexico City, Claudia Sheinbaum, designated Florencia Serranía [es] as the general director of the STC. Serranía had previously held the same position from 2004 to 2006 during the governorship of Andrés Manuel López Obrador, who was president of Mexico at the time of the collapse.^[13] From 2020 to April 2021, the position of STC deputy director-general of maintenance was vacant, and Serranía assumed management of that role.^[14][15]

 

Line 12, often known as the Golden Line due to its color on the system map, operates from south-central Mexico City to the semi-rural southeastern borough of Tláhuac, serving approximately 350,000 passengers daily in 2019. As of May 2021, it was the newest line in the Metro system.^[8][7]

The head of government of Mexico City, Marcelo Ebrard, announced the line in August 2007, and construction commenced in September 2008.^[16][17] Originally, the line was planned to be primarily underground, featuring 23 stations—20 of which were to be underground from Mixcoac to Nopalera, while the last three—Zapotitlán, Tlaltenco and Tláhuac—were intended to be at-grade stations.^[18] It was also expected to run underneath Eje 3 Oriente.^[19] The original budget for the project was MX$14 billion pesos.^[20]

The opening was initially expected to coincide with the 200th anniversary of Mexico's independence in 2010.^[21][22] Multiple construction delays postponed its inauguration by Ebrard and required intervention from the federal government, led by Felipe Calderón.^[23] The project was modified to have nine underground stations from Mixcoac to Atlalilco, nine elevated stations from Culhuacán to Zapotitlán, and Tlaltenco and Tláhuac as at-grade stations.^[21] Additionally, the elevated section would run along Avenida Tláhuac instead of Eje 3 Oriente.^[24] The elevated sections were constructed using concrete columns that support two parallel metal beams to hold up the girders, with foundations built on rocky soil.^[25]: 54

The line was constructed by Empresas ICA in association with Alstom Mexicana and Grupo Carso, the latter owned by business magnate Carlos Slim.^[26] It was Carso's first project in railway construction, and they built the bridge between Calle 11 and Zapotitlán stations.^[27][28][29] Ebrard and Calderón inaugurated the line in October 2012 a few months before the end of their terms.^[7][30][31] The project's cost soared to MX$26 billion pesos (US$1.29 billion as of 2021).^[30][32]

 

The FE-10 train model, manufactured by Construcciones y Auxiliar de Ferrocarriles (CAF), is exclusively used on Line 12. Unlike other lines in the system, which generally use rubber tires—except for Line A—the FE-10 uses steel wheels. Francisco Bojórquez, the then-general director of the Metro system, advocated for rubber tires, considering them a safer option. However, an internal labor commission disagreed, supporting the use of the more cost-effective steel wheels.^[33]

Line 12 was designed similarly to Line A, taking into account the specifications of Bombardier trains, which have a width of 2.50 meters (8 ft 2 in) and a weight of 170 metric tons (170 long tons; 190 short tons) per railcar. In contrast, the FE-10 trains are wider and heavier, measuring 2.80 meters (9 ft 2 in) in width and weighing 240 metric tons (240 long tons; 260 short tons) per railcar.^[34][35] The FE-10 trains have a capacity of 1,900 passengers and are designed as gangway models, allowing users to move between cars.^[25]: 40

CAF received a concession for the trains from 2010 to 2026, under a contract worth US$1.588 billion; this was the first time that STC did not directly purchase the trains.^[36] SYSTRA, a multinational engineering and consulting group, reported that train operations were within accepted safety limits.^[37] Technischer Überwachungsverein recommended replacing the trains due to excessive wear on the wheels and rails caused by their incompatibility.^[38]

 

Line 12 encountered issues with trains on elevated sections during its construction. Before pre-operational testing began, topographic monitoring detected subsidence on several columns.^[35] Personnel recorded vibrations on the tracks in the Tláhuac borough area. Passenger testing commenced in June 2012; the Metro system noticed damage to approximately 10,000 ties due to vibrations in the following months.^[35] Operations necessitated speeds as low as 5 km/h (3.1 mph) on some segments. A congressional report indicated that coupling unprotected rails with wheels that did not meet required standards could lead to train derailments.^[7][30]

In March 2014, the elevated section was closed for twenty months for repairs due to technical and structural faults.^[7][39] The city government established a special board to investigate the causes of the problems and hold officials accountable for the errors that led to the partial closure.^[40] Among those investigated were Mario Delgado, the city's Secretary of Finance, and Ebrard, who went into self-imposed exile in France in 2015, saying he was the target of a political vendetta created by his successor, Miguel Ángel Mancera.^[41][42][43] Thirty-three officials and former officials, including Enrique Horcasitas, the director of the Line 12 project, faced sanctions that included disqualifications from public work, fines, or both.^[44]

Mancera's administration hired SYSTRA in 2014 to conduct an independent investigation and provide a report. After reviewing over 2,900 documents and testing the tracks, the team concluded that errors occurred during the "planning, design, construction, and operation" of the line.^[45][46] In a non-public report published by SinEmbargo.mx after the collapse, SYSTRA noted that the wear and tear observed was unusual for a project that was only up to two years old, which they attributed to "mediocre quality" work. The group concluded that to avoid future problems, the Metro system would need to address the root causes of the wear, as repairs would only serve as temporary fixes and the defects would likely reappear. They notified government authorities that a permanent resolution to the issues would not be feasible and recommended developing a maintenance manual customized to the line's requirements for continuous operation.^[47]

The Superior Auditor of the Federation (Auditoría Superior de la Federación; ASF) identified in 2015 twelve irregularities in the construction process, including the incompatibility between the train wheels and the rails, which could lead to track instability, while noting that train operations were within accepted safety limits.^[48] CAF refuted the claims that the wheels and rails on Line 12 were incompatible.^[49] According to Serranía, the French company Tricaud Société Organisée (TSO) was contracted in 2016 to maintain the daily operating conditions of the line's fixed installations and reported no concerns before the collapse.^[50] The cost to address these issues exceeded MX$1.2 billion pesos.^[51]

The 2017 M_w7.1 Puebla earthquake damaged the line's tracks, leading to the temporary closure of six stations, from Tezonco metro station to the eastern terminal.^[52][53] Tezonco and Olivos stations reopened three days later, with Olivos serving as the provisional terminal for about a month while repairs were made to the other stations.^[54][55] The Associated Press reported that experts advised closing the line for a comprehensive inspection instead of merely reinforcing it.^[52] The ASF noted damage to the section that eventually collapsed.^[56] Following the earthquake, residents reported visible structural cracks in the structure, prompting transport authorities to address these complaints.^[4] In January 2018, they also repaired a column between Olivos and Nopalera stations that had cracks in its base.^[57][58]

Before the COVID-19 pandemic in 2020, residents provided photographs and videos to the authorities, expressing concerns that the bridge was buckling and that the structure was moving abnormally as trains passed.^[59] By the end of 2019, the engineering firm Ingeniería, Servicios y Sistemas Aplicados (ISSA) conducted a study on the structural and geotechnical behavior of the overpass, concluding that there was no risk to the line's operation.^[50]

 

On 3 May 2021 at 22:22 CDT (UTC−5), an eastbound train was traveling on the track between Olivos and Tezonco stations in Tláhuac.^[60][61] Approximately 220 meters (720 ft) before reaching Olivos station,^[62] the section of track between columns 12 and 13 collapsed due to a failure of the girder, causing the rear two train cars to derail.^[63][64][65] The fallen railcars formed a V-shape, with one car coming to rest on the ground and the other left suspended.^[30][66] Debris from the collapse struck a vehicle traveling on Avenida Tláhuac, resulting in the death of the driver and injuries to his wife.^[67] The overpass was approximately 5 meters (16 ft) above ground level, situated over a concrete median strip, which helped to minimize casualties among motorists and pedestrians below.^[68]

A total of twenty-six people died in the collapse, including fifteen who died at the scene, while ninety-eight others were hospitalized.^[1][69] It marked the deadliest event for the Metro since 1975, when a collision between two trains resulted in the deaths of thirty-one passengers at Viaducto metro station.^[70] It was also the third fatal accident within fourteen months.^[64] Following the collapse, twenty-two individuals were reported missing; however, by 6 May, the number of unaccounted individuals was reduced to five.^[71][72] According to the city government, it is likely that none of these individuals were on board the train, as they had been missing for several days prior to the accident.^[73]

Rodrigo García, the driver of the crashed train, felt a jolt just before arriving at Olivos station, after which his control panel indicated a power failure. García activated the emergency brake, exited the cab, and observed smoke and passengers evacuating from the last car. The control center instructed him to assess the situation and reassure the passengers accordingly. He was later informed of the collapse. In the fifth and last available car, García encountered injured and unconscious people, estimating that the train was three-quarters full.^[74]

The STC warned residents to avoid the area.^[75] Witnesses initially began rescue efforts, later joined by first-response teams.^[76][77][78] Neighbors provided rescuers with coffee, water, and bread.^[79][80] A nearby shopping mall cleared its parking lot to allow authorities to establish a control post.^[81] Rescue operations were suspended after a few hours due to the structure instability.^[82] A crane was deployed to lift sections of the train while search-and-rescue teams looked for survivors.^[83] The first train car was removed the following day at 09:20 CDT, and the second car was removed before 14:00 on the same day.^[81] All debris had been cleared by the end of the month.^[84][85]

 

Service on the entire Line 12 was suspended.^[86][87] The following day, a rail replacement bus service was established, utilizing 490 city buses, which were inadequate to meet passenger demand. To enhance the service, the city contracted additional buses from Autobuses de Oriente and approved temporary routes to Tasqueña, Universidad, Atlalilco, and Coyuya metro stations.^[88] The federal government declared three days of national mourning.^[89] Social media users reported structural damage at other elevated stations, including Oceanía, Consulado, and Pantitlán; Sheinbaum stated that these stations would be inspected.^[90] The general secretary of the Mexican Union of Metro Workers announced that approximately 8,000 workers would go on strike due to unsafe working conditions.^[6][70]

The office of the federal Attorney General (FGR), along with its Mexico City counterpart (FGJCDMX) led by Ernestina Godoy Ramos, and the Norwegian risk management firm Det Norske Veritas (DNV) were appointed to investigate the collapse.^[91][92] Sheinbaum stated that the families of those who lost their lives would receive MX$700,000 (US$35,000) each,^[91] which included MX$50,000 (US$2,500) from the city and MX$650,000 (US$32,650) from the Metro. This compensation was later increased to MX$1,870,000 per family.^[93]

When Serranía was asked about satellite images showing that the collapsed section was slightly warped, she stated, "There is no such information; it is not true".^[50] The National Regeneration Movement (MORENA), the ruling party in Mexico, voted against the establishment of a special commission to investigate the collapse, referring to the proposal as "scavenger" and asserting that the collapse had no "urgent and obvious resolution".^[94] Sheinbaum and Ebrard, both former heads of government of Mexico City, are protégés of López Obrador and were considered leading candidates for MORENA in the 2024 presidential election—which Sheinbaum ultimately won.^[95] According to international journalists, the collapse could have impacted their presidential campaigns, as Ebrard oversaw the construction of Line 12, regarded as his "signature infrastructure project", while Sheinbaum had over two years to address concerns about the line's condition and ensure its proper maintenance.^[6][32][95]

 

Minutes after the collapse, Sheinbaum arrived at the accident site.^[96] Ebrard, who was the Secretary of Foreign Affairs at the time of the incident, expressed on Twitter, "What happened today in the Metro is a terrible tragedy ... My sympathy to the victims and their families".^[97] The following morning, president López Obrador extended his condolences and stated, "Nothing will be hidden; we should not fall into speculation ... no accusations will be made without evidence".^[64][98] Carso announced that they would await the official expert analyses before making any statements regarding the incident.^[28][99]

In the days following the collapse, protesters expressed their anger over the incident and the authorities' responses by vandalizing several Metro stations, breaking glass partitions and painting slogans such as "It wasn't an accident—It was negligence" on the walls.^[100][101] Demonstrators marched from Periférico Oriente metro station to the accident site, carrying banners that read "It was not an accident; those responsible have first and last names" and "Corruption kills, and the dead are always the people".^[102] Residents also set up an altar in a shopping mall near the site of the collapse.^[103] On 7 May, hundreds of protesters held a vigil at the scene, demanding justice.^[104]

For the Day of the Dead observance in 2021, local residents encouraged others to create a thematic altar called "Train to Mictlān".^[105] On the eve of the first anniversary of the collapse, the National Action Party (PAN), an opposition party, installed a temporary sculpture on Paseo de la Reforma in front of the Antimonumento +43 memorial. It referenced the overpass collapse and featured the inscriptions "#FueMorena" (#ItWasMorena) and "La tragedia de la Línea 12" (The Tragedy of Line 12) on a wine-colored plinth, reflecting MORENA's institutional colors.^[106] On the anniversary of the collapse, family members, survivors, and residents visited the site to place altars and candles. They informed journalists of their intention to request permission from the city council to establish a memorial at the site of the collapse.^[107]

 

 

 

Some photographs from the first DNV report illustrate the root causes of the collapse. The top image features red circles marking studs with remaining ceramic protection, highlighting surface deficiencies at the joint, while red arrows indicate uneven spacing. The center image identifies the location of the studs (circled in red) and shows concrete differences from that of the prefabricated girder (blue rectangle). The bottom image depicts poor welding causing insufficient fusion to the girder.

On 5 May 2022, the city government contracted DNV to conduct a detailed, independent investigation into the collapse.^[108] The investigation was divided into three parts, each with a specified payment: the first part, costing MX$8,169,343 pesos, would address the preliminary causes of the accident; the second part, which would include the immediate cause, was set at MX$5,049,743 pesos; and the final part, costing MX$9,394,914 pesos, would focus on the root cause and provide recommendations for the line's reopening.^[109][110] According to the contract, DNV was authorized to "collect information for documentary analyses, covering design, construction, rehabilitation, intervention, operation, maintenance, and supervision" of the line up to the date of the collapse.^[111]

DNV published the first part of the report on 16 June 2021, which identified structural faults associated with six construction deficiencies:^[112]

• Poor welding process of Nelson studs;
• Porosity and lack of fusion in the stud–beam joint;
• Insufficient Nelson studs in the beams spanning the bridge assembly;
• Use of different types of concrete in the girder;
• Unfinished or improperly executed welds; and
• Inadequate supervision and dimensional control in fillet welds.

DNV investigated the adequacy of the design and materials used for the line, assessed whether the structure's performance met the design requirements, and evaluated how operations, repairs, and renovations had affected the bridge.^[112] The group reported that fewer bolts than necessary to support the structure had been installed and that the concrete covering them might have been faulty.^[113] Additionally, in August 2010, supervisors issued an alert regarding the construction of the Tezonco–Olivos overpass, indicating that only ten reinforcement bars were to be used in the bridge, despite the original project plans specifying twenty.^[114] According to El Financiero, the report did not include four additional lines of inquiry: "lateral-torsional buckling of the steel beams", "crushing of the concrete slab", "influence of loads from the railroad system", and "lack of infrastructure maintenance".^[115]

DNV was initially expected to deliver the second part of the report on 14 July 2021; however, the group postponed it until 7 September of that year.^[109][116] In the 180-page investigation, DNV concluded that the collapse was caused by a lack of functional Nelson studs in the affected section, which resulted in the buckling of the north and south beams. This caused the girders to function independently in conditions for which they were not designed, leading to distortion in the central transverse frame and fatigue in the support. Additionally, poor distribution of the existing bolts and inadequate welds in the area further contributed to the collapse.^[117][118]

The third part of the report was initially expected in August 2021 but was delivered on 28 February of the following year.^[109][119] The city government rejected the report's conclusions and withheld its publication. On 4 May 2022, Sheinbaum acknowledged the report, describing it as a "deficient, poorly produced, ... tendentious and false" document that presented "technical issues". She claimed it served the interests of opposition parties and stated that DNV had unilaterally altered the methodology originally presented when the firm was hired. She also asserted that the company had a conflict of interest because one of DNV's lawyers had previously litigated against López Obrador. Additionally, she announced a civil lawsuit against DNV and indicated that the firm would not receive payment for the final part of the report.^{[120][121][122]} Andrés Lajous, head of the city's Secretary of Mobility, explained that the change in the report's methodology pertained to DNV's decision to "plant maintenance" as a cause of the collapse.^[123] DNV maintained that their report was delivered "in accordance with the agreed RCA [root cause analysis] methodology and to strict internal quality and revision procedures". The firm added that Héctor Salomón Galindo Alvarado, the referred lawyer, was hired in July 2019 and has no authority over the reports or investigations conducted by the company or being contracted by DNV México.^[124][125]

On 9 May 2022, the Spanish newspaper El País published part of the third report, in which DNV concluded that the root cause of the accident was the bridge's design not complying with construction standards. Key factors included the lack of certification by an independent entity, inadequate supervision, changes to the original design, misplaced, poorly welded, or missing studs throughout the girders, and a lack of maintenance inspections from 2012 to 2019, despite recommendations for thorough annual inspections in the manual provided by ICA–Carso–Alstom.^[126][127] The city government released the report two days later and explained the discrepancies they identified during a conference. Officials expressed their opposition to the report because:^[128]

• DNV did not compare the collapsed section with similar segments;
• DNV relied on Google tools, including Google Street View, despite a disclaimer indicating that the data may not reflect actual conditions;
• DNV initially claimed that the deformations were not visible to the naked eye but later contradicted this by using Google Street View images;
• The ICA–Carso–Alstom maintenance manual did not specify methodologies for assessing deformation criteria;
• The report initially stated that no maintenance reports were provided but later acknowledged that reports for 2019 and 2020 did exist; and
• DNV did not follow the requested methodology.

Sheinbaum announced that the contract with DNV would be terminated and that a group of engineers would be hired to "present the complete truth".^[129]

 

Three days before DNV released its report, journalists from The New York Times (NYT) published an investigation stating that the collapse was attributed to a series of errors originating in its planning. The report indicated that the line was built hastily as Ebrard's administration was nearing its end, with steel studs connecting the steel to the concrete slab failing due to poor-quality welds and the failure to remove ceramic rings. It also noted that the city approved substandard work and that audits after the 2017 earthquake revealed errors in the original construction, including missing steel components and improperly poured concrete.^[130] Sheinbaum criticized the NYT article, asserting she did not leak information to a publication that opposed the Fourth Transformation—the president's political platform.^[131] Ebrard stated that the collapse resulted from a lack of maintenance rather than structural faults.^[132]

The FGJCDMX investigation found results similar to DNV's initial report. It revealed that shear bolts connecting the concrete slabs to the beams were misaligned, and in some cases, the studs were not fused with the beams, causing distortion-related fatigue. The report concluded that the collapse occurred when the eastbound beam suddenly failed, dragging the westbound beam down within 1.9 seconds.^[133][134] Additionally, a study by specialists for the attorney general's office indicated that the collapsed section had only 65 percent of the necessary bolts.^[135] They also noted a lack of inspection reports addressing bridge issues, stating that existing deformities and defects could have been identified with proper maintenance and specialized examinations.^[136]

The College of Civil Engineers of Mexico (Colegio de Ingenieros Civiles de México; CICM) conducted independent studies of Line 12, excluding the collapsed area. They found that the bridge features two types of girders: concrete girders built by ICA from Culhuacán to Calle 11 stations, and steel girders built by Carso from Calle 11 to Zapotitlán stations.^[29][28] The study revealed that 68 percent of the elevated section exhibited minor and common deficiencies, while the remaining 32 percent—located between Periférico Oriente and Zapotitlán stations—showed vulnerabilities requiring further analysis. These vulnerabilities included poor welds, improper spacing between beams, cracks in columns and beams, and irregularities in the steel structure support.^[29][137]

Sheinbaum stated that the reconstruction of the collapsed section was anticipated to be finished by the end of 2022.^[138] A week after the collapse, STC contemplated reopening only the underground segment.^[139] However, the CICM advised against this, recommending a reinforcement and rehabilitation project before any reopening.^[140] They also cautioned against reopening the underground section, as the railway workshops necessary for train maintenance are situated beyond Tláhuac station.^[141]

In June 2021, Sheinbaum discussed with ICA and Carso their potential financial responsibility for the reconstruction of the elevated section.^[142] On 22 June, López Obrador met with Sheinbaum and Slim, where they reached an agreement that Slim would assist with the reconstruction. López Obrador emphasized the urgency, stating that the work should be completed "as soon as possible" and aimed for Line 12 to be operational again "within a year at the latest, with full safety".^[143][144] A week later, López Obrador announced that Carso had agreed to rebuild the collapsed section at no cost,^[145][146] and Slim remarked:

I am convinced that [the line] was built by the best engineers in Mexico, who did the calculations and the design, and if you remember, in October 2012, around November ... the project was approved, which had been done by international experts. I am convinced that from its origin, it has no flaws. So much so that the president of the Republic, the head of government, and the elected head of government rode on it, and many of us were invited to tour it, covering about 12 kilometers (7.5 mi).^[a]

 

Reconstruction of the collapsed section began on 16 February 2022.^[148] A total of 6.7 km (4.2 mi) underwent strengthening with column reinforcements and supports, including struts, diaphragms, and tensors.^[149] Additionally, a girder located 200 metres (660 ft) from the accident site will be dismantled and rebuilt. According to Guacamaya Leaks, which involved multiple internet leaks of classified documents from the Secretariat of National Defense by the hacktivist group Guacamaya, Mexico City authorities requested the army to donate 20,000 t (20,000 long tons; 22,000 short tons) of steel for the girders' reinforcement. This steel was originally intended for the canceled Texcoco Airport, and the army provided 13,000 t (13,000 long tons; 14,000 short tons).^[150] Sheinbaum confirmed this information, stating that the unused material from the construction of Felipe Ángeles International Airport was repurposed for the reinforcement of Line 12.^[151]

The subway section of Line 12, which runs from Mixcoac to Atlalilco stations, reopened on 15 January 2023.^[152] In preparation for the section reopening, 15,000 ties and rails were replaced in several interstation tunnels, leaks were repaired, and the track ballast was upgraded to a firmer material. The section operated thirteen trains and was patrolled by members of the National Guard, who were deployed to all metro stations following the 2023 Mexico City Metro train crash, amid Sheinbaum's allegations that the system was under attack from saboteurs.^[153][154] The next section, from Culhuacán to Periférico Oriente stations, opened on 15 July 2023.^[155] The last section, including the area where the collapse occurred, reopened on 30 January 2024.^[156]

After the first DNV report on the collapse was released, Grupo Carso lost MX$7.8 billion pesos on the Mexican Stock Exchange.^[157] They faced an additional loss of MX$2.7billion pesos after announcing plans to rebuild the collapsed section.^[158] On 28 June 2021, Serranía was removed from her position and replaced by Guillermo Calderón, the general director of Servicio de Transportes Eléctricos.^[159] Just days before the second report's delivery, DNV filed a complaint with the FGJCDMX due to a breach in the chain of custody regarding a package sent to the United States for further studies. Upon its return to Mexico, the box containing the samples had been tampered with, which could impact the investigation.^[160]

In August 2021, the FGJCDMX initiated an investigation into eleven welders and two supervisors.^[161] By October, charges of manslaughter, injury, and property damage were announced against Horcasitas, along with nine former officials and supervisors. Many of these individuals had been disqualified from public office in 2014 and 2015 for their roles in the project's planning and construction.^[162][163] Horcasitas' defense argued that errors arose when the city sought to modify the original project and contracted different companies, claiming that the line's infrastructure had not received proper maintenance since its opening.^[164] The defense also pointed out that the Spanish version of DNV's report omitted maintenance-related information.^[165] The ten former officials were formally charged in December 2021 and were awaiting trial as of January 2023.^[166]

Carso estimated that the reconstruction and reinforcement of the collapsed bridge would cost MX$800 million pesos.^[167] In November 2021, the company stated that in 2010, it subcontracted the stud-welding company J. J. Jiménez, S. A. de C. V., and that Carso supervised the work through a verification system that assessed the welding of the studs, their alignment, and their final positions.^[168]

By February 2022, 80 percent of those affected had received compensation from Carso as part of a deal stipulating that they would not pursue legal action or seek additional payments in the future.^[169] This percentage increased to 90 percent by May 2022.^[170] Compensation amounts varied based on the severity of injuries, ranging from MX$450,000 pesos (about US$21,600) to six million pesos (approximately US$290,000) for the families of deceased victims. Carso also retained the right to seek reimbursement from those found legally responsible for the collapse and to take legal action against them.^{[169][171][172]} By February 2022, the remaining parties who had not accepted the compensation were pursuing legal action against Carso.^[173]

• "Línea 12 puede puede colapsar sin mantenimiento: TSO" [Line 12 can collapse without maintenance: TSO]. Forbes México (in Spanish). Mexico City. 7 April 2014.
• "Mexico City Government Reports Technical and Scientific Inconsistencies Found In Phase III Report Submitted by DNV on Metro Line 12". Government of Mexico City. 11 May 2022.
• Lagunas, Icela (November 2021). Línea 12: Crónica de una tragedia anunciada [Line 12: Chronicle of a tragedy foretold] (in Spanish). Planeta Group. ISBN 9786070781902.
• Zerega, Georgina (28 April 2022). "Un peritaje presentado por víctimas del desplome de la Línea 12 del metro apunta a fallas en el diseño, la construcción y el mantenimiento" [An expert report submitted by victims of the collapse of Metro Line 12 highlights flaws in design, construction and maintenance]. El País (in Spanish). The article includes a 26-minute video featuring Tomás Andrade Ramos, an architectural engineer, who explains the structure's composition and the factors that contributed to the collapse.

External videos
The collapse

• Line 12 openness website by the Government of Mexico City (in Spanish)
• DNV's technical report of the accident, published by the Government of Mexico City (in Spanish)