"[2] The project consists of the rehabilitation of the Tehuantepec Railway, which finished construction during the presidency of Porfirio Díaz in 1907, which was built with similar goals, but started to fall out of use upon the outbreak of the Mexican Revolution and the opening of the Panama Canal in 1914.

[3] Due to the short distance between the two oceans in this area, the potential for the creation of such a project had been attractive to various global powers, including Spain, Britain, France, the Netherlands and finally the United States, as it would have saved cost and time.

In the Essay, he mentioned multiple points in the Spanish Americas where the two oceans could be connected, including the Isthmus of Panama (belonging to the Viceroyalty of New Granada), remarking the fact that Vasco Núñez de Balboa successfully crossed it as early as 1513 (several years before Mexico was conquered by Spain), but that since then, at the time of the work's publication, no survey of the region nor the determination of its exact geographic position had been made, despite propositions being made since 1528 suggesting cutting that Isthmus and joining the sources of local rivers.

[6] Indeed, he also remarked that Viceroy Juan Vicente de Güemes, 2nd Count of Revillagigedo, "has been for a longtime occupied" in the project of the creation of such a canal, and that land-based roads had been opened in the Isthmus since the late 18th century, which created commercial communication between the two oceans; these were used, he remarked, to transport "the most precious of all known indigoes," the indigo from Guatemala (then a kingdom belonging to New Spain covering much of Central America, bordering Panama, though, according to Humboldt, it "depends very little on the viceroy of New Spain"), and cacao from Guayaquil (in modern-day Ecuador, then part of the Real Audiencia de Quito) to Acapulco and, from there, to Vera Cruz to be sent to Europe, so as to avoid the dangers and difficulties of navigation to and through Cape Horn.

[6] He remarked in the Essay the natural beauty and rich resources of the intendancy of Oaxaca, where Tehuantepec is located, and stated that the port "will become one day of great consequence when navigation in general, and especially the transport of the indigo of Guatimala, shall become more frequent by the Rio Guasacualco [sic].

However, the concession would have expired in July 1844 since the project fell stagnant due to a lack of funds (despite getting access to free labor from three hundred convicts in October,[11] also secured by Bocanegra), but Garay asked for a two-year long renewal a few days before the deadline.

Trist continued to insist, but ultimately failed at his objective and no mention of the right of passage through the Isthmus of Tehuantepec was included in the Treaty of Guadalupe Hidalgo, signed on 2 February 1848 to end the war.

In June, despite it being the rainy season in the Isthmus, a local engineer named Peter E. Trastour was sent to the Pacific Coast to conduct a survey, delivering his preliminary report in October despite facing much hardship.

Additionally, due to the distance saved while traveling to the American West Coast from New Orleans, New York or England, the report claims that it "is therefore plain that the superiority of Tehuantepec over all other routes is immeasurably great.

When U.S. President James Buchanan sent Robert Milligan McLane to Veracruz, who arrived on April 1, to establish diplomatic relations with the best suited party, he was given instructions from Secretary of State Lewis Cass to negotiate a treaty to purchase Baja California, if possible, and the American right to use the Isthmus of Tehuantepec "in perpetuity" and Northern Mexico for military and commercial transportation for $10 million dollars.

The Conservative government, likewise, referred to the treaty's negotiators as "traitors to the nation," manifesting their discontent to France and the United Kingdom, even asking for military intervention to the Emperor of the French Napoleon III,[24] an event which would eventually contribute to the beginning of the Second Franco-Mexican War in the following decade.

The Liberals suffered a series of significant losses during the period of negotiations, including Tacubaya just days after McLane's arrival, and the Conservatives held strong influence by the end of 1859 in areas such as Aguascalientes, Zacatecas and San Luis Potosí.

[22] Ultimately, despite the controversial concessions Mexico gave in the treaty that benefited the U.S., it failed to be ratified by the U.S. Senate, to Buchanan's regret, largely due to the political division between the Southern and Northern states which eventually led to the American Civil War.

The exact circumstances of this are somewhat debated, though it is widely believed that the conflict between protectionists and supporters of free trade, as well as the Southern advocates of actual annexation of Mexican territory, were significant in the failure of the treaty's ratification.

[9][27] Despite the failure of the previous attempts and controversial events surrounding the usage of the site, businesses and the government continued to show their interest in the creation of a communication line between the two oceans through the narrow Isthmus, and so, during the presidency of Porfirio Díaz, himself a man from Oaxaca, the project of a railway in the Isthmus of Tehuantepec would start to get shape, this time insuring the neutrality of the passage and that the Mexican nation would preserve its sovereignty, now that it enjoyed political stability and had a strong standing army, which was respected internationally due to its victories during the country's wars against Spain and France.

The company would be in charge of modernizing the railways, the building of a telegraph system, two new ports; Salina Cruz, Oaxaca, to open up to the Pacific Ocean, and Coatzacoalcos, Veracruz, to the Atlantic; and of maintenance and administration.

Under the administration of Enrique Peña Nieto, a plan was made to develop the economy through the creation of seven areas known as Special Economic Zones (Zonas Económicas Especiales, "ZEE" by its initials in Spanish and "SEZ" in English), but, as the project kept being postponed until 2017, the penultimate year of his presidency, little could be done regarding this.

[40] In a controversial instance, in July 2023, it was announced that 200 trees would be cut down in the municipality of Salina Cruz for the construction of the Corridor, without offering much other information, at that time, about the business involved in the operation (later identified as ABCD ARQUITECTURA S.A. DE C.V., which is also responsible for the construction of the Coatzacoalcos railway station)[41] or its environmental impact despite the requests of local communities,[42] though the municipal council did agree to requests to spare some of the trees depending on their age, size and location, and to form a strategy to avoid massive deforestation.

In late November 2022, Marín Mollinedo announced his intention to step down from his position as director of the CIIT, to become the head of the National Customs Agency of Mexico [es], a request which became effective before December 15.

[48] On the early morning of 19 May 2023, with the permission of a presidential decree, the Mexican Armed Forces took control of 127 km (79 mi) of the railways belonging to Ferrosur, a company owned by the conglomerate Grupo México, in Veracruz, sparking controversy.

[46][55][56] The still president-elect announced Vice-Admiral Juan Carlos Vera Minjares, who was in charge of the Unit of Infrastructure and Transportation of the Corridor, as his replacement on 30 September, just hours before Sheinbaum officially became the president of the country.

Crowds of locals gathered around the Tehuana with cheers and applause, as it was the first time the tracks had been used in over 25 years, since President Ernesto Zedillo privatized the railway sector, and as they expect for the Corridor to become an economic driver for their communities.

[73] However, on 23 February 2024, without explaining many details, the Pole of San Juan Evangelista was declared deserted by the Corridor's general director Morales Ángeles, even though a representative of Urcedic was an honored guest during the inauguration of Line Z's passenger train.

[140] The former general director of the CIIT Rafael Marín Mollinedo agrees with this idea, since the Panama Canal "is saturated and cannot cope with all the demand," thus he states that "we don't call it an alternative, we prefer to refer to it as a complement.

"[29] In September 2023, it was reported that the South and Southeast of Mexico, as a result of the various megaprojects López Obrador's administration has developed in the region, including the Corridor, has experienced unprecedented levels of economic growth after facing decades of stagnation.

[109] Carlos Corral Serrano, executive director of the Mexican Association of Urban Planners (Asociación Mexicana de Urbanistas), has found the existing infrastructure of the region insufficient and in need of improvement.

[151] Independently from these factors, the British newspaper Financial Times reported on 16 October 2023 that international shipping companies and other such entities have yet to show significant interest for the Corridor; an executive at Unique Logistics, for example, stated that whenever an alternative trade route is available, importers become highly skeptical and unsure of whether they should use it or not due to their lack of knowledge on its reliability.

[153] Prior to this, on April 28, a violent incident occurred in the site of Mogoñé Viejo, in San Juan Guichicovi, when Mixe activists clashed with the authorities after two months of blocking the Corridor's workers from rehabilitating a portion of the Transisthmian Railway.

"[30] The Indigenous peoples desire, above all other services, better agricultural infrastructure which does not negatively interfere with the local biodiversity and their traditions, in addition to the depollution of the land and water, hence the environmental concerns due to the industrial parks.

[158] In late July, 23 civil society organizations registered, after three days of investigation, various violations to human rights in the Isthmus region related to the construction of the Corridor, such as intimidation from members of the Mexican National Guard, in Santa María Mixtequilla, to members of the Community Assembly and people who showed resistance to the project, illegal occupation of lands, dispossessions and acts of physical aggression against comuneros and comuneras in the town of Santa Cruz Tagolaba, in Tehuantepec, among other violations in other sites committed by the National Guard, the Armed Forces, the state police and other authorities, businesses and armed groups.