22 ENVIRONMENTAL CONNECTION / THIRD QUARTER 2025 / IECA.ORG Figure 2. The seven sections of the Maya train. the most appropriate products, the technical specifications of the main commercial brands available in the market and the Biobased certificate were reviewed to comply with the project requirements. It was concluded that the products that best met the technical requirements were High Density HMI for the cellulose component and Rainier Premium and Fiber Plus for the wood fiber component. For the construction phase of the railway, the Mexican government divided the project into seven sections, which were awarded to major local and international construction companies. These companies contracted with Mexican contractors specialized in hydroseeding. Two Mexican companies were responsible for the hydroseeding application across multiple sections of the railway. This article focuses on the work performed by one of these companies, Corporativo Mayra, which was involved in the final phase of the Tren Maya’s construction. This company was responsible for hydroseeding four sections covering 313 miles (505 km), with a total area of approximately 300 acres (125 ha). The project area is characterized by a tropical climate throughout the year, with high temperatures and a pronounced rainy season lasting half the year. The following sections provide data on average rainfall and temperature for Campeche, Quintana Roo and Yucatán, where most of the railway is located. There is a substantial difference between the dry season (December to May) and the rainy season, which begins in mid-June and extends until November (Figure 3). Temperature variations throughout the year are relatively small. The annual average temperature ranges for the three states go from 75.38 F to 90.26 F (24.1 C to 32.3 C) (Figure 4). Many different hydroseeders were used to meet needs of the project. The amount of hydroseeding materials per acre applied to embankment slopes is detailed in Figure 5. The terrain configuration along the railway varies, with embankments featuring 45-degree slopes of varying lengths and heights (Figure 6). Additionally, there are a few sections with 90-degree rocky slopes covered with three- >> dimensional mesh to be revegetated (Figure 7). Certain underpasses feature structures resembling gabion walls, locally known as “Tai walls,” which also required hydroseeding. During the hydroseeding application, logistical challenges arose, primarily regarding water availability, which was managed by the construction companies involved in the project. The hydroseeding sections lacked nearby surface water sources, such as rivers, small creeks or lakes, and water access points were limited and often distant. Moreover, water tankers were also in demand for construction activities at the same time. To address this issue, coordination was established with contractors to ensure the necessary daily water supply and, in some cases, implement a night shift to apply hydroseeding (Figure 8). The selected grass seeds were tropical, noninvasive, non-aggressive, certified and commercially available. Annual ryegrass exhibits rapid germination of six to nine days and provides quick surface coverage due to its fast growth. Braquiaria, on the other hand, germinates within 10 to 12 days and grows more slowly until it develops additional leaves. Once annual ryegrass completes its life cycle in 10 to 12 months, it decomposes, enriching the soil with organic matter. Monitoring visits were conducted to assess germination rates. Initial evaluations indicated lower-than-expected germination due to high temperatures causing excessive evapotranspiration, leading to rapid soil drying. Post-seeding irrigation was managed by the construction contractors. During evaluations, findings were shared with them to improve irrigation practices. The absence of significant rainfall in the early months further complicated the situation and prompted recommendations for early morning INTERNATIONAL PEER REVIEW
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