At the beginning of the century, there were only two railways in Patagonia. Both were privately owned, and were far from integrating a network. One was the 1 m-gauge Puerto Madryn to Trelew line, which belonged to a British company and had been promoted by the Welsh colonists in Chubut. The other was also British owned, the Bahía Blanca-Neuquén broad gauge line belonging to the Southern Railway Company. There was also a private service operating between Salinas Grandes and Puerto Pirámide in the Valdés Peninsula (Chubut) and a small train in use at the Ushuaia federal prison (Tierra del Fuego).

In 1908 the Argentine Congress passed Law 5559, fostering the development of the National Territories. Minister Ramos Mexía had inspired the law, which promoted the integration, by rail, of potentially productive areas on the Andean valleys and the vast Patagonian tableau, linking trains with waterways and seaports.

Law 5559 authorised the Executive Power to plan, build and operate two railway lines from Puerto San Antonio and Puerto Deseado on the Atlantic coast, reaching Nahuel Huapi lake on the Andean Cordillera. Branches were to be built to Comodoro Rivadavia (through Colonia Sarmiento), Lago Buenos Aires (through Colonia Las Heras), Colonia 16 de Octubre (the Esquel and Trevelin area), and any other that the Executive deemed convenient. However, soon the original project came to a halt because of Minister Ramos Mexía's resignation in 1913 and the subsequent outbreak of World War I.

Of all these projects, only a part of the Ramos Mexía original plan was completed. Rails were laid on 282 km between Puerto Deseado and Las Heras (Santa Cruz province), and 197 km between Comodoro Rivadavia and Colonia Sarmiento (Chubut province). But they were never linked with the main railway under construction between Puerto San Antonio and Nahuel Huapi lake (San Carlos de Bariloche). The line reached Km 448 (Ingeniero Jacobacci station) only in 1916, this point being afterwards the end of the tracks for a long time. Of Law 5559's railways, it was the only one that was continued in the following years, and it finally reached San Carlos de Bariloche on the Nahuel Huapí lake in 1934.

When World War I ended the National Government modified its original plans, and decided to build the railway branch to Colonia 16 de Octubre using the low-cost 0.75m gauge. To better understand the motivations behind that decision, we must bear in mind that the narrow Decauville railways ( 0.60 m ) had been widely used for carrying supplies to the front during the war. And after the war ended, they played an important role in the reconstruction of the battlefields in France and Belgium

Imported from Europe and laid as feeder branches for the broad gauge main line towards Bahía Blanca cargo terminals, these inexpensive narrow gauge Decauville railroads had ample success in many agricultural areas in southern Buenos Aires province, as Balcarce, Cascallares, Copetonas and Orense. Four networks were established; in total 372 km of tracks that soon carried thousands of tons of freight.

Argentina's economy had suffered considerably during World War I, as the country's international trade had been greatly reduced. In the midst of a post-war recession, funds available for the completion of the Patagonian network of 'development railways' were limited. Therefore, the narrow gauge was regarded as a feasible solution. Most probably the 0.75 m gauge was chosen because these locomotives were readily available from some manufacturers.

Although using narrow gauge for such an ambitious project seemed inadvisable, late in 1921 a decision was made to buy all the necessary railway material, not only to join Colonia 16 de Octubre with Ing. Jacobacci, but also to extend this branch to reach the Puerto Madryn-Dolavon one metre gauge line. It was the birth of the Patagonian Light Railways Network, which included our cherished Old Patagonian Express " La Trochita."

The passenger coaches, livestock carriers and freight wagons were purchased in 1922. This was done in two separate orders from the Belgian company Atelliers de Construction de et a Familleureux, totalling 230 flat trucks, 150 open wagons, 110 boxcars, 100 cattle wagons, 100 sheep wagons, 35 water tank wagons, 35 oil tank wagons, 50 'fourgons' for 'mixto' (mixed) trains, 25 first class coaches, 25 second class coaches, and spare parts for all this rolling stock.

The first 50 steam engines were ordered from the German company Henschel & Sohn, which afterwards also provided 4 shunter locomotives and 2 crane tanks. Later, a further 25 locomotives were ordered from The Baldwin Locomotive Works of Philadelphia (U.S.)

Therefore, the total acquisitions for the 0.75 m gauge railways were:

79 locomotives
50 passenger coaches
50 'fourgons' / baggage cars / cabooses
690 freight wagons (including livestock carriers)
70 tank wagons
2 shunter locomotives
1,390 km of rails, including accessories

All this material was stocked at Madryn and San Antonio ports; the rails were afterwards carried to Ing. Jacobacci (Km 448 on the San Antonio-Nahuel Huapi line).

By a National Decree of October 7, 1922, the original Patagonian railways plan was modified and extended to cover 1,225 km . But later the construction was never completed.

Without delay, once the construction materials were available work started on placing a third rail inside 16 km of the broad gauge, from Km 448 (afterwards Ing. Jacobacci) westwards, so as to allow the new narrow gauge to run on these same tracks. On the Atlantic coast, the third rail for the narrow gauge was also placed inside the broad gauge from Trelew to Dolavon, and afterwards the 0.75 m line was extended westwards to reach Alto Las Plumas, near the Upper Chubut River Valley. From Trelew, a new narrow gauge line was constructed eastwards reaching Rawson and Playa Unión on the sea. In this way, first steps were taken to link the Atlantic with the Andes by train, integrating a network of 0,75 m gauge railways.

In 1931-32 great floods destroyed large parts of the embankments and many bridges and culverts. The floods spared only short sections of the railway under construction, so the engineers had to reconsider the whole project. The works started again in 1934, now with steady progress, and the Government provided the necessary funds on a continuing basis.

Among the necessary constructions there was a 105 m-long bridge to be built on the Río Chico, and a 110 m-long tunnel. Almost a thousand people worked at the branch. Many came from all around the world as immigrants, including Macedonian, Greek, Croatian, Slav, Turkish, Indian, Ukrainian, and Polish citizens. Workers were organised as independent crews, each working on its assigned sector. Camps were groups of simple corrugated iron huts, in a region where extreme temperatures are frequent both in summer and winter. Although they withstood a particularly hard working environment, many of them afterwards settled permanently, forming families that became strongly integrated with Patagonia.

Trains started running as from 1935 on the first stretches of the narrow gauge railway. The surveying and construction plans to Esquel were finished in 1937. In 1941 the Railway reached El Maitén, where the line's main workshops were built, and finally, on May 25, 1945, " La Trochita " made its triumphant entry in Esquel.

Albeit its construction was slow, and the Patagonian railways network never came to be true, this railway produced a significant impact on the region.

Until 1950 the railway operated exclusively as a freight service from and to Esquel, a fact that clearly shows the importance of commerce in those years. Most of the manufactured goods and building materials came from the north by railway, reaching this part of Patagonia after being transhipped to the narrow gauge at Ingeniero Jacobacci. Accordingly, the wool, skins, and livestock that were locally produced were shipped north from Esquel and some of the stations that dotted the narrow gauge line along the Argentine Southern Land Company’s farms.

The passenger service was inaugurated in 1950. The line connected with the broad gauge at Jacobacci, and then proceeded north through San Antonio, Viedma, Carmen de Patagones, and Bahía Blanca, reaching Buenos Aires at Plaza Constitución terminal. Passengers from the narrow gauge arrived in Jacobacci after a long journey, and the most well-off had a broad gauge sleeping car waiting for them on a siding. This car was afterwards coupled to the train coming from Bariloche, upon its arrival some hours later.

During the 1950s and 1960s, up to three weekly services were run on both directions of the narrow gauge, carrying sometimes as much as 200 tonnes of freight. As late as the 1970s, many of the building materials for the Futaleufú dam were brought in on “La Trochita.”

El Maitén was born with the railway. When the railway crews arrived, firstly the bridge on the Chubut river was built and then the line’s main workshops erected. Later, up to 200 railwaymen worked at these shops. Nowadays they are still in operation, but with a much-reduced workforce now employed by the Chubut Government. Most of the remaining Baldwin and Henschel locomotives are kept there, and a few are still running owing to these people’s efforts and knowledge.

Back in the 1960s, while stressing the steam train’s charm, a famous character in the Argentine film ‘The Patagonian Professor’ leaned out from one of its small windows, and exclaimed: “Here, you can breathe Patagonia from all sides!”. And despite the narrow gauge’s troubled history, that exhilarating sensation the unforgettable actor Luis Sandrini expressed in this film can still be experienced today, when travelling through the southern vastness on board of “La Trochita.”

This process gradually continued towards its final closedown, a decision made in 1992 and executed in 1993. The Puerto Madryn-Trelew-Rawson-Alto Las Plumas branch had already been closed years before in 1961. The Puerto Deseado-Las Heras and the Comodoro Rivadavia-Colonia Sarmiento branches had met the same fate in the 1970s.

Undeniably, when the roads and trucks improved in Argentina they quickly displaced the less-competitive state railways. But it is also a fact that “La Trochita” could not escape the general decline of what once ranked with the great railway networks in the world (and the only significant one in Latin America).

This disintegrating process hit the Patagonian railways really hard, as they never reached their network stage, and ran through sparsely populated territories. Their importance was primarily of a social nature, and therefore they were unattractive to private capital, just as they had always been.

But something happened with La Trochita. This branch had become famous, and beloved by Argentines and foreigners for different reasons. Backpackers that travelled during their summer holidays on it, the press, cinema, television, and even international literature had made it famous. And when its closedown was imminent and everything seemed lost, there was a clamour from all sides not to allow the trencito to die.

In 1992 the New York Times published an article by Nathaniel Nash, titled “For the Patagonian Express Fate”. Mr. Nash wrote:

“The truth is the railway’s name is not The Old Patagonian Express; that title was invented by Theroux for his book. It is far from being an express, panting along the tracks and emitting great clouds of black smoke, not only stopping at its fourteen official stops, but many times more when finding passengers midway. Argentines call the train La Trochita. On each trip, people occupy all the loose wooden benches and drink yerba mate, the Argentine hot beverage, and gather around the small wooden stove in the middle of each carriage, jolting on their 14-hour long journey to Esquel. The only hope for its survival lies in persuading investors about La Trochita’s historical and tourism value. As one Mayor told me, this is one of the world’s most singular journeys, on one of the planet’s most singular places. People are always impressed by Patagonia.”