Consequently, on October 3, 1900, the first route between Barcola (a seaside resort near the famous Miramar Castle of Maximilian of Austria) and Boschetto (a densely populated district of Trieste) was inaugurated: curiously, almost of the same itinerary of the first horse-drawn tramway.

Every car carried a “train number”, that distinguished any vehicle on the same route (this system – by little dox-matrix indicators – is still valid today, on the buses of “Trieste Trasporti”).

Verify the success obtained by electric trams, the Municipality of Trieste decided to realise and to manage directly further routes, but the licensee STT taken a legal action in order to stand up for oneself.

The Supreme Court of Vienna (until 1918, Trieste was part of the Austrian-Hungarian Empire), however, issued on May 19, 1910 a sentence in favour of Municipality.

The new Administration of the Municipality, in order to raise the decent profit resulting from public transportation, decided to take it upon itself the whole net of STT, starting from 1921.

[1] The last route, the "11", opened on December 23, 1928, and ran from the center of the town to “Rion del Re”, a new neighborhood built in the hills in the south-east of Trieste.

At the same date, the network reached to the maximum extension, with 124 trams and 86 trailers in service and with 11 routes covered about 45 km (28 miles):[1] In 1934 the Municipality decided to unify the public utilities and create the A.C.E.G.A.T., acronym that means “Council Society for Electricity, Gas, Water and Tramway”.

In order to significantly reduce the costs, it was considered fit to replace the conductors with automatic ticket machines: for many factors, A.C.E.G.A.T.