The management of this line was transferred to the Grand Duchy of Baden State Railways, which began operating 17 daily passenger trains in each direction.

An expansion of services between two cities, however, was not possible because of the limited capacity of the main line between Karlsruhe and Ettlingen West, so the construction of a direct rail link to Rüppurr was soon discussed.

In order to remove the smoke produced by the steam locomotives of the Alb Valley Railway from the streets of Karlsruhe, the Karlsruhe-Ettlingen section was electrified at 550 volts direct current in 1898 and a service with electric multiple units was added.

Since electrical operations on the line were well-proven, an extension of electrification was considered for the whole Alb Valley Railway, but with high-voltage alternating current preferred because of the greater distance.

Technical problems and a lack of thermal coal forced the BLEAG in 1917 to greatly limit operations with electrical rolling stock, sometimes abandoning the service entirely.

Through modernisation, including the introduction of transporter wagons (Rollwagen), the DEBG succeeded in improving the financial viability of the railway.

In the Second World War the Alb Valley Railway was attacked several times by fighter aircraft, but damage was relatively minor.

However, the demolition of the bridge over the Karlsruhe marshalling yard at the end of the war required several months of reconstruction to restore the Alb Valley Railway to the southern bridgehead at Dammerstock.

From then on the electric multiple units of the Alb Valley Railway continued from the Albtalbahnhof to the centre of Karlsruhe, so that most passengers did not have to change trains.

[3][4] Additional sections were opened to Ettlingen on 15 May 1959, to Busenbach on 15 April 1960, to Etzenrot on 12 May to 1960, to Marxzell on 12 December 1960 and to Herrenalb on 1 September 1961.

[4] Even after the gauge conversion of the line between 1957 and 1975, the line continued to be modernised, including the building of a signalling centre in Ettlingen (1967), the realignment of the Albtalbahnhof–Dammerstock section (1977) and the Rüppurr–Ettlingen Neuwiesenreben section [1988), the upgrading of the track to allow a top speed of 80 km/h (until 1983) and the duplication of track between Ettlingen and Busenbach (1989–1990).

Track improvements were also carried out in Steinhäusle in order to create a request stop, which was composed only of a platform next to a level crossing and was paid for by nearby residents.

Services on the metre gauge Alb Valley Railway between Karlsruhe and Herrenalb had a running time of about 70 minutes.

In doing so, the Albtalbahn became the first element in the Stadtbahn Karlsruhe, which has subsequently become a model for using tram-train techniques for linking regional railway routes to municipal tram systems in other European cities.

However tram-trains running on the Alb Valley Railway continue north of the Albtalbahnhof to join the city tram tracks of the Verkehrsbetriebe Karlsruhe.

The line to Bad Herrenalb is 15.8 km (9.8 mi) long and passes through five intermediate stops before reaching its terminus.

The Albtalbahnhof (Alb Valley station) on Ebertstrasse, which was originally built in 1915, was rebuilt after the gauge conversion with four platform tracks and connected via a triangular junction to the Karlsruhe tram network.

A connecting track was built to Karlsruhe Hauptbahnhof, which allows services through the Albtalbahnhof to continue on the lines to Durmersheim and to Karlsruhe-West.

The tracks were rebuilt in 2006 and supplemented by a bridge that takes the Ittersbach line over the neighbouring highway, eliminating a very busy level crossing.

The main workshop of the AVG, which was built in the early days of the Alb Valley Railway, was west of the line to Herrenalb until 1971.

In addition to the canopy built in 1978 that spans all three tracks, a water crane, a historical, mechanical destination display, a bell and a semaphore signal were installed.