[2] As of 2006, the tram system included approximately 308 kilometres (191 miles)[2] of narrow and standard gauge one-way track.

[2] The realization of the idea to build a network of tram lines in Sofia began on December 1, 1898, when the Sofia Municipality granted a concession for the construction of tram lines to companies from France and Belgium.

The construction work lasted about a year and on 1 January 1901 the first tram in Sofia officially started.

Theodosii Kardalev began production of the first Bulgarian trailers, which used sturdy chassis from already scrapped railcars.

In 1936, the first Bulgarian railcars were produced under the brand name "DTO" (Дирекция на трамваите и осветлението - Direktsia na tramvaite i osvetlenieto: Department for trams and lighting, owned by Sofia municipality).

In 1934, the first large tram depot was built on the territory of today's Krasno Selo municipality.

Then the Sofia Tramway Plant launched two new tramcar models: the "Komsomolets" in 1959 and the "Kosmonavt" in 1961.

Based on the experience gained with the Komsomolets and Kosmonavt, and taking into account the design flaws and shortcomings (they paid a very high price with more than 40 killed due to the practical lack of brakes), a new two-section tram was developed and launched in 1965.

Due to incidents, the three-section trains "Sofia 70" and "Bulgaria 1300" do not run on lines with complex curvilinear/inclined sections: from Pl.

The last Bulgarian double-articulated tram T8M-900, which is still in service today, was produced in the factory in 1991.

Until that time all lines were nominally metre gauge, but actually constructed to a width of 1,009 mm (3 ft 3+23⁄32 in).

No other tram lines have been built since then, as Sofia has focused its efforts on the construction of its metro system.

[2] Tram line 21 was temporarily opened with a route from the bus station Iztok to Kv.

And in the 21st century, with the expansion of the Sofia metro, many of the tram lines were shortened or closed entirely.

However, the city council never returned the tram line, and the tracks from Hemus Hotel to the Spartak Pool in Zh.k.

Lines 1 and 7, due to the construction of the metro, no longer run on Pedestrian Vitoshka, where the first tram in Sofia passed in 1901, causing congestion on Hristo Botev Boulevard and amortization of the tracks.

Letters from tram letterboxes are collected at several junction stops in the city centre and handed over to Central Post Office for processing.