Belgrano Sur Line
The Belgrano Sur line is an Argentine  commuter rail service in the Greater Buenos Aires area, currently operated by state-owned enterprise Trenes Argentinos. The Belgrano Sur runs over tracks and stations built by the Franco–Belgian-owned Compañía General de Buenos Aires and British Midland companies at the beginning of the 20th century.

The termini is Dr. A. Sáenz in the Nueva Pompeya district of the autonomous city of Buenos Aires, with two branches to 20 de Junio (departing from González Catán) and Marinos del Crucero Gral. Belgrano in La Matanza and Merlo partidos respectively. Carrying just under 11 million passengers per year, the line is the least used of the Buenos Aires commuter rail network.

History

Background

The railway line was originally built and operated by two companies, British-owned Buenos Aires Midland Railway that made its inaugural trip in 1909 joining Puente Alsina and Carhué, and Franco-Belgian-owned Compañía General de Buenos Aires (established in 1908), that built and operated a large network reaching cities in the west of Buenos Aires Province and branches to cities such as La Plata and Rosario, although most of the line was closed and only a few services are active nowadays.

When the entire Argentine railway network was nationalised in 1948 during Juan Perón's presidency, the BA Midland became part of the Belgrano Sur line division of the General Belgrano Railway. Furthermore, the now nationalised companies added to Ferrocarril Belgrano network had been renamed, being known as "G" (Cía. Gral. de Buenos Aires), M (Midland) and P (Province of Buenos Aires Railway).

Ferrocarriles Argentinos
After the nationalisation, several improvements were carried out in the line, such as the addition of a rail track between Aldo Bonzi and Libertad to increase the frequency of the services. The modernisation included the purchase of brand-new diesel locomotives by American company Whitcomb in 1951 (with the addition of 15 new ones by Werkspoor in 1955) and the construction of a junction in the Tapiales and Aldo Bonzi stations that allowed the ex-Midland line to connect with the Sarmiento Railway near Haedo in Greater Buenos Aires.

During the 1950s, the increasing population in Greater Buenos Aires led the company to add more services. By December 1955, the Belgrano Railway ran more than 40 services per day in the Puente Alsina−Aldo Bonzi section. Nevertheless, the rolling stock had not been renewed since the 1930s and as a result, some railcars that had crashed or been destroyed in accidents were put out of service and never replaced due to the lack of investment to acquire brand new material.

In the late 1960s and early 1970s railcars by Hungarian company Ganz Works were sent to the Belgrano Sur. They had been acquired by the Argentine State Railway decades earlier and had been running in Northern Argentine railways since 1936. Some of them were used for local services to Libertad and the rest for the long distance service to Carhué, departing from Buenos Aires station, the former Compañía Gral. de Buenos Aires terminus. The Ganz railcars ran services until 1977 when the line was definitively closed.

When the Libertad−Plomer section was closed, Buenos Aires station of ex-CGBA was set as the terminus. Trains ran without passengers from Puente Alsina to Aldo Bonzi, running back to Tapiales junction where they departed to Buenos Aires station. Passengers waited and took the train in Buenos Aires, being carried to Carhué via Plomer. The lack of maintenance caused a progressive deterioration in the rolling stock and stations of the line, therefore the line was closed in September 1977 and workshops at Libertad were demolished.

On 2 March 1977, Decree N° 547 by de facto President of Argentina, Jorge Rafael Videla ordered the closure and dismantlement of more than 4,000 km of rail tracks. Several General Belgrano Railway lines were closed on 1 May, although long distance services to Carhué continued operating until August when the last train ran to that city. Nevertheless, the closure of services in the region did not make a negative impact on the economy of the Province since the rail tracks crossed along low-populated regions. Furthermore, most of that region was already served by other railway lines with better access to the city of Buenos Aires.

Privatisation: Metropolitano
With the railway privatisation in Argentina in the early 1990s, the Belgrano Sur line had been granted in concession to private company Metropolitano starting operations in 1994. Nevertheless, the Government of Argentina revoked the contract of concession in 2007 due to the poor conditions of the service and increasing complaints from users. Until then, the concessionary had been receiving near $ 30 million of subsidies per month.

In the first years of private operation, many kilometres of the line were closed with stations and infrastructure abandoned. In spite of the large government subsidies received by TMB (the Metropolitano's division that operated the line) a serious decline in the standard of their rail services led to the original concession being revoked. In 2007, the service was given in concession to the consortium UGOFE.

Transition and new concession
The UGOFE took over the service until February 12, 2014, when it was announced that the Belgrano Sur and Roca lines would be granted to Argentren S.A., a company part of the Emepa Group and the UGOFE was immediately dissolved.

Renationalisation and investment

The State-owned company Trenes Argentinos took over Belgrano Sur line (operated by Argentren) after the Government of Argentina rescinded the contracts signed with the company on 2 March 2015. The contract terms specified that the concession could be cancelled with no right to claim compensation. The agreements had been signed in February 2014, committing Argentren and Corredores Ferroviarios to operate the lines.

In September 2013, the Government of Argentina announced that 23 brand-new railcars were acquired from Chinese company CNR Dalian. New rolling stock was expected to be run from May, 2015, However, the first coaches (out of 81) arrived in Buenos Aires in July so they will be running on the line from August, 2015. By the end of July, another set of trains had arrived in Buenos Aires and it was announced that the testing of the new rolling stock had been completed, and they would begin running on the Buenos Aires - Gonzalez Catán route in August. The other parts of the line will receive the new rolling stock before the end of 2015, as they arrive in the country.

It was also announced that all the 28 stations of the line would be remodelled. The cost of the investment was estimated in A$ 1,200 million. The platforms of the stations are being elevated to match the height of the new rolling stock, while track is being refurbished on the line with the Buenos Aires - Tapiales segment receiving completely new rails on concrete sleepers. 24 of the stations will be completely replaced using modular designs, while some single-track segments will be made into double-track segments.

Two important extension works are also currently being studied and undertaken. To the southwest, the section from González Catán to Marcos Paz (closed at the time of privatisation) will be restored and reopened, extending that branch of the line after its 20-year closure whilst adding new overpasses and connecting the line with the Merlo - Lobos branch of the Sarmiento Line. Similarly, there are also plans to bring the line further into the city, moving the terminus from Buenos Aires station to Constitucion railway station where it will connect with the Roca Line and Line C of the Buenos Aires Underground. The construction will use viaducts to avoid level crossings in the city and is being carried out in cooperation between the National Government and the Government of Buenos Aires.

In December 2019, the service was extended 9 km from González Catán to 20 de Junio in La Matanza Partido. Passenger trains had't stopped in 20 de Junio since 1993, when services were reduced to reduce costs.

Rolling Stock 
In August 2015, the first diesel multiple units acquired from CNR Tangshan were put into service. This rolling stock consists of 81 cars, which make up a total of 27 DMUs composed of three cars each and will be phased-in throughout the year until the line is made up entirely of these trains.

Prior to the complete replacement by the Chinese DMUs, the line consisted of a variety of diesel locomotives pulling carriages in a number of different combinations. The incorporation of the new rolling stock means doubling the line's passenger capacity.

Services 
The Belgrano Sur line operates the following diesel-engined services: