ASF Flags Overpayments in Iztapalapa Elevated Trolleybus Works

ASF’s Public Account 2024 audit of Calzada Ermita Iztapalapa elevated trolebús works flagged MX$57.54 million pending clarification, including MX$20.01 million (US$1.16 million) in overpayments. The review cites differences between paid and physically verified quantities, unit-price and calculation errors, and missing supporting documentation, and issued five statements of observations.

Mexico’s top federal auditor, Superior Auditor of the Federation (ASF) has identified overpayments and documentation gaps in works carried out by the Ministry of Infrastructure, Communications, and Transport (SICT) for a mass-transit project in the east of the Valley of Mexico, including the electric transport system, trolleybus over Calzada Ermita Iztapalapa on the Acahualtepec-Santa Martha section.

The findings are included in ASF’s Compliance Audit of Physical Investments 2024-0-09100-22-0349-2025, titled “Integrated Transportation System in the Eastern Zone of the Valley of Mexico, in Mexico City and in the State of Mexico.”

According to the audit file, SICT reported MX$597.30 million (US$34.77 million) as spent in 2024 on the project, and ASF reviewed a MX$362.17 million (US$21.08 million) sample, representing 60.6% of the year’s outlays.

ASF’s review focused on three contracts, two public works contracts and one supervision-related services contract, covering construction and oversight tied to the trolebús corridor and related structures around Santa Martha.

ASF lists the following contracts as part of the audited sample:

• 2023-15-CE-A-018-W-00-2023, a unit-price public works contract for the construction of the electric transport system over Calzada Ermita Iztapalapa, Acahualtepec–Santa Martha section. ASF’s table also records multiple modifying agreements, including schedule changes and a temporary suspension due to lack of resources, and notes that by the time of ASF’s review (August 2025) the works were concluded and in close-out.

• 2023-15-CE-A-019-W-00-2023, a unit-price public works contract for Phase 1 of the Santa Martha station and a curved viaduct connection on the Mexico City side, also with several modifying agreements and a temporary suspension. ASF similarly reports the works were concluded and in close-out by August 2025.

• 2023-15-CE-A-015-Y-00-2023, a related services contract for supervision of the trolleybus construction over Calzada Ermita Iztapalapa (Acahualtepec–Santa Martha) and the Santa Martha station works, including quality verification. Unlike the two public works contracts, ASF states that by August 2025, the supervision services were still in execution.  

In the audit’s results section, ASF reports overpayments totaling MX$20.01 million (US$1.16 million) across contracts 018 and 019, driven by differences between estimated and paid quantities versus those physically verified for multiple work items, as well as one concept executed with different characteristics than those paid. 

ASF then details additional overpayment findings and support deficiencies, most of them tied to contract 018, that collectively underpin the total amount the auditor is asking the agency to clarify.

Beyond quantity differences, ASF highlights several issues related to the way unit prices were built and applied:

• MX$4.29 million (US$249,710) in overpayments in contract 018 linked to an “extraordinary unit price” concept related to fluid fill. ASF says that the cost used for this input was MX$1,200/m³ (US$69.85), but that it should have been MX$1,056.91/m³ (US$61.52), based on the date of the bid opening and presentation of proposals. 

• MX$1.46 million (US$84,984) in overpayments in contract 018 tied to the incorrect integration of eight extraordinary unit prices, where ASF indicates the analyses considered direct input costs above what was determined under the applicable increases/decreases communicated through SICT notices, again referenced to the bid presentation and opening date.

• MX$910,000 (US$52,969) in overpayments in contract 018 for concepts associated with supplying and placing structural steel and steel plates, where ASF reports arithmetic errors in calculations across several estimates. 

ASF also flags a major support issue, MX$30.87 million (US$1.80 million) in payments under contract 018 for a concept related to installation of induced works, where ASF says that supporting documentation was not integrated to substantiate how the direct cost was determined, including supporting expense documents and productivity/yield assumptions for labor and equipment. 

Putting the findings together, ASF points to a total MX$57.54 million (US$3.35 million) pending clarification. 

ASF also reports that it determined eight results, where two had no irregularities and one was addressed before the report’s issuance, while the remaining results generated five statements of observations. These are formal observation briefs through which ASF requests clarification, documentation, corrective actions, and where applicable, recovery of funds. 

ASF dates the audit conclusion to Feb. 4, and states that SICT generally complied with applicable rules except for the observed issues described in the report.