 On 16 September 1969, during the protest movement known as the Rosariazo, eight Fiat vehicles were destroyed, and three MAN and 14 other vehicles were damaged to varying degrees.Following these events, services on line H were suspended, because the 32 surviving units could only cover the requirements of lines K and M.

In 1970, 12 Mercedes-Benz "0 km" trolleybuses (manufactured in 1953 for the city of Bahía Blanca, but not used there) entered the Rosario fleet, plus 11 vehicles that had been withdrawn from service in Mendoza.The arrival of these 23 units enabled the reintroduction of services on line H in 1971.