On 21 January 1877, the first horse-drawn tramway was opened from Gottesauer Platz to Mühlburger Tor in an east–west direction through the city of Karlsruhe.
In the same year, this was followed by a branch line to the old railway station and an approximately 2 km (1.2 mi) extension from Mühlburger Tor west to Mühlburg.
So the ownership of the tramway changed several times in the early years of its existence, until a permanent solution was found with the founding of the Vereinigte Karlsruher, Mühlburger und Durlacher Pferde- und Dampfbahngesellschaft (United Karlsruhe, Mühlburg and Durlach Horse and Steam Railway Company).
The tram network was not electrified until 1900, but a compromise meant that overhead lines were not built through the centre of Karlsruhe and instead were operated with accumulator cars.
Three years later, the city centre route was equipped with an overhead line and the accumulator mode was abandoned, so that all cars could be used everywhere.
In the following years the tram network was extended to some of the newly created suburbs (Oststadt, Weststadt, Südweststadt) and was to the nearby towns of Beiertheim.
The importance of the tramway for the urban development prompted the city of Karlsruhe to acquire the tram service from AEG in 1903 and operate it as a municipal undertaking.
Compared to the period of horse and steam operations, the expansion of the network accelerated and passenger traffic rose rapidly.
Also in 1929, the newly opened outdoor swimming pool of Rheinstrandbad on the island of Rappenwört was connected to Karlsruhe.
Blackout measures were taken as a protection against air raids: headlights and windows were partially covered and the trams were given a grey camouflage.
Due to the fuel shortage, truck operations were restricted during the war years, so trams carried mail between Karlsruhe station and the main post office as well as fruit and vegetable shipments from the market hall to various retailers.
Soon after the Second World War a structural change occurred in an urban development that had a significant impact on public transport and so also for Karlsruhe.
In parallel with this there has been a change in the economic structure: the large factories in the city were abandoned and new industrial and commercial areas were developed on the outskirts.
The difficult economic situation of the 1930s and material deprivation and destruction during the Second World War did not permit modernisation of vehicles and equipment.
The acquisition of the Alb Valley Railway and the Busenbach-Ittersbach railway along with the Albtal-Verkehrs-Gesellschaft (Alb Valley Transport Company, AVG) in 1957 and their regauging and connection to the tramway network allowed AVG vehicles to operate on the tracks of Verkehrsbetriebe Karlsruhe, giving direct services between the surrounding countryside and central Karlsruhe.
Further enhancements in the region came after 1979 with the integration of the Hardt Railway in the AVG and the development of the Karlsruhe model of tram-train operations.
Passenger numbers only rose with the expansion of the network from the 1980s, the introduction of regular interval operations on a clock-face schedule and attractive fares and a greater environmental awareness among the people.
[3] Since the 1960s, there have been attempts to build a tramway tunnel in the centre of Karlsruhe to relieve the main shopping street of trams.
At the end of 2005 the so-called "combined solution" (Kombilösung) for the Stadtbahn tunnel completed the planning approval process.
[4][5][6] In June 2007, the Federal Republic of Germany, the state of Baden-Württemberg and the city Karlsruhe agreed on the allocation of costs.
The urban environment will benefit as a result of the elimination of the tram tracks in the pedestrian zone and the rebuilding of Kriegsstraße.
A citizens' initiative against the combined solution was launched in the summer of 2009 to require a third referendum,[7] but this failed in the administrative court.