In recent days, a news report documented damage to Section 5 of the Maya Train, including exposed steel, loose concrete, corrosion, and demolition and shoring work. One of the testimonies gathered indicated that train traffic continued during the repairs, despite the risk.
In an interview with Prensa IBERO, Agustín Ortega García, Coordinator of the Master’s Program in Engineering with a Specialization in Construction Management, and Alan Sánchez Pulido, Coordinator of the Bachelor’s Degree in Civil Engineering at the Universidad Iberoamericana (IBERO), noted that the construction of the section was marked by planning failures, a lack of geological studies, and the absence of regulatory standards.
Specialists from our university explained that much of the visible damage on Section 5 of the Maya Train is consistent with the challenges of building heavy infrastructure on karst terrain, which is characterized by cenotes, caverns, and underground cavities.
They explained that working on columns or supports while rail traffic is active is technically feasible, but only under highly controlled conditions and with constant monitoring.
They noted that there are international standards that allow work to be performed on structures under construction provided that train speeds are reduced, loads are limited, and there is continuous monitoring of structural behavior.
According to those interviewed, any temporary shoring must be capable of supporting 100% of the vertical loads and approximately 70% of the horizontal loads.
However, they cautioned that in Section 5 of the Maya Train project, the damage detected is located on terrain with cavities and material loss, making it difficult to find safe points to support temporary reinforcement structures.
They noted that placing a load on a structure that is no longer 100% intact alters its original strength, forcing the redistribution of stresses to other structural elements.
The experts considered it very risky to remove three supports simultaneously and explained that every structure is designed to distribute loads among multiple load-bearing elements; by removing several supports at the same time, stresses in other areas increase critically, compromising the structure’s stability.
Although they acknowledged that it could technically be done if adequate shoring were in place, they noted that the ideal approach would have been to carry out the work one section at a time to minimize risks.
They also stated that maintaining regular train service during this type of work involves accepting a considerable degree of uncertainty, and they pointed out that Mexico lacks specific regulations for structural interventions of this kind.
Incompatibility between the construction method and the limestone terrain
They explained that the structures seen in the images released are piers rather than pilings. They explained that this system involves drilling into the subsoil, temporarily filling the hole with bentonite slurry, placing reinforcing steel, and then pouring concrete to great depths.
The problem, they noted, is that in karst (limestone) terrain with cracks, caverns, and underground voids, there is no absolute certainty about where the concrete flows during pouring.
“The concrete was flowing away, disappearing through the cracks,” they explained, describing how some of the material could have been lost inside natural cavities without any immediate way to verify it visually.
Both agreed that the foundation system was not flawed; in fact, they considered the piers to be excellent for supporting heavy loads.
The problem, they said, was the lack of sufficient subsoil studies that would have allowed the construction process to be properly adapted to the actual ground conditions.
They noted that, for environments with humidity, salinity, and the potential presence of hydrogen sulfide, special sulfate-resistant concrete, thicker steel coatings, anti-corrosion systems, and even stainless steel should have been used.
They explained that there are international specifications for infrastructure in marine or highly corrosive environments, but Mexico lacks specific railway regulations for scenarios such as that of the Maya Train.
The experts questioned the choice of the railway route. They noted that the region’s geological limitations had long been known and that the right-of-way of existing roads—where the ground had already been excavated and stabilized—could have been utilized.
In their view, they agreed that attempting to build an elevated viaduct over cavernous areas ultimately shifted the environmental impact from the surface to the underground ecosystem.
Professors Sánchez Pulido and Ortega García believed that there was structural overdesign resulting from technical uncertainty. They compared the case to the reinforcements applied after the collapse of Line 12 of the Mexico City Metro, where large amounts of steel and reinforcements were added due to the lack of certainty regarding the structure’s actual behavior.
“When you don’t know exactly what’s working and what isn’t, you end up adding more steel and more components,” they noted.
In their view, these decisions drive up costs, make the structures less efficient, and reflect ethical and planning issues.
They insisted that the viaduct requires constant inspections and real-time monitoring because processes such as corrosion, erosion, and chemical degradation can worsen rapidly, even within weeks.
They considered monthly inspections insufficient and noted that passenger safety must be the central priority of any infrastructure project.
The experts noted that technical infrastructure decisions should not be subject to political or administrative timelines, as this shifts risks onto the end users of the project.
Original text by Luis Reyes published in Ibero.
Translation by Schools for Chiapas.