[4] They worked the first line G, which linked the Plaza Sarmiento with the intersection of Avenida San Martín and Saavedra, where there was a mini terminal for connections to the south.

Over time, the line was extended to the intersection between Salta and Paraguay, then to Calle San Nicolás, and, two years later, to the Mariano Moreno bus station.

On 15 April 1960, line H was opened, with a route running from the Plaza Sarmiento to the city's northern boundary, with Granadero Baigorria.

Between August and December 1961, brand new Fiat trolleybuses arrived in Rosario, allowing network expansion with the creation of new lines.

At the request of residents, it was extended in 1964 to the corner of Paraná and 9 de Julio, in front of the Rosario Oeste railway station of the Ferrocarril General Manuel Belgrano.

[8] Around May 1980, concessionaire EMF acquired five large Soviet ZiU trolleybuses with three doors, but these vehicles had been poorly maintained, and were in service in Rosario for a very short time before being scrapped in 1984.

During their limited time in service, they nevertheless created a favorable impression, due to their size and interior capacity, and air suspension.

After a long series of vicissitudes and mismanagement by the private concessionaire, the trolleybuses on the system were declining in quality of service and maintenance.

Following a new call for tenders, the concession to operate line K was awarded in late November 1992 to a joint venture (Spanish: Unión Transitoria de Empresas (UTS)) composed of Capse SA (public lighting concessionaire) and Molino Blanco SRL (concessionaire of urban passenger transport lines 133 and 143).

The concessionaires were required to operate 20 trolleybuses, renovate feeder substations and make good the overhead wire network.

They were also expected to extend the route network: Ciudad Universitaria at one end and Mendoza and Wilde at the other; the latter was only partially realised initially, as far as Calle Sánchez de Loria.

The new trolleybuses arrived in late 1993[9] in the form of 20 units with Volvo chassis, bodywork by Brazil's Marcopolo and electrical equipment by Powertronics.

During the 1993 suspension of trolleybus service, construction of the planned extensions proceeded, east to Ciudad Universitaria and west to Calle Sánchez de Loria.

[14] On 15 July 2003, route K was extended farther at its west end, by around 500 metres, to a roundabout at Bulevar Wilde,[15] making its overall length 12.6 km end-to-end.

Trade union disputes coupled with a poor relationship between the concessionaire and the municipality were the triggers for the termination of the concession in October 2004.

[22] The 1961-built trolleybus was fully restored to operating condition and historic paint scheme and was given its original fleet number, 39.

08, has also been designated for eventual preservation as a historic trolleybus, and for this reason SEMTUR intentionally excluded it from a 2010–11 programme under which all 19 others of the type were rebuilt by ArMar Carrocerías.