Overall, it crosses five mountain ridges between the valleys of the Pfinz, Walzbach, Saalbach, Kraichbach, Elsenz and Lein, requiring three tunnels.

After crossing the Rhine Valley Railway, running between Karlsruhe and Heidelberg by a bridge on which Hubstraße Stadtbahn stop is located, and running parallel with the Karlsruhe–Mühlacker railway, it changes its safe-working system from the tram operating procedures (BOStrab) to rail operating procedures EBO shortly before Grötzingen.

The Kraichgau Railway branches off at Grötzingen Oberaustraße station, running from Jöhlingen West to Wössingen Ost as a two-track line.

At Bretten station it passes over the Württemberg Western Railway on a bridge, which is now served by Karlsruhe Stadtbahn line S 9 and regional service R 91.

To accelerate construction, the city of Karlsruhe, under Mayor Wilhelm Florentin Lauter, offered to build the Baden section to Eppingen as directed with the Grand Duchy of Baden State Railway to operate the line, initially paying rent and later buying the line by instalments.

This was operated along its entire length by Württemberg, including the section through Baden territory between Ruit (near Bretten) and Bruchsal.

Because the Baden railways had a financial crisis, the city of Karlsruhe found it difficult at first to find a contractor to build the line, so that it was not until 15 November 1876 that a contract could be issued.

During the discussion of the remaining section of the route the council of the then independent municipality of Stetten am Heuchelberg presented the designers with a fait accompli: it built a local station before it was clear that the line would pass through the site at all.

The towns of Dürrenbüchig and Gölshausen (now both districts of Bretten) that are located on the Kraichgau Railway had complained about not having stations.

In 1888 the Bretten–Eppingen–Heilbronn section of the line was duplicated as part of a military supply route from central Germany via Nuremberg, Crailsheim, Heilbronn, Bretten, Bruchsal, Zweibrücken in the Saarland to Lorraine.

The importance of the connection in peacetime, however, remained low, and the administrators of the Kraichgau Railway did not listen to requests for fast trains between Karlsruhe and Würzburg/Nuremberg.

[2] On 31 March 1920 the Baden and Württemberg State Railways were absorbed into the newly founded Deutsche Reichsbahn.

Efforts were made in subsequent years to duplicate the remaining single section between Durlach and Bretten, without success.

At the same time some track was dismantled to allow the re-opening of the Bietigheim viaduct on the only rail link between Karlsruhe and Stuttgart in August 1945.

As a result, the Albtal-Verkehrs-Gesellschaft (Alb Valley Transport Company, AVG), an undertaking of the city of Karlsruhe, took over, from about 1990, the funding of the modernisation and electrification of the line as a pilot project.

This form of operations is known as tram-train and its adoption on the Kraichgau Railway was the final step in the development of the Karlsruhe model.

On 10 December 2005 Stadtbahn services were extended to Öhringen after two years of construction on a section of the Hohenlohe Railway.

The platform height above rail level in Wössingen Ost, Bretten, Gölshausen Industrie and all stations between Eppingen and Heilbronn is 55 cm, thus making possible level access to the Stadtbahn vehicles of class GT 8-100D/2S-M. All other stations have a platform height of 38 cm.

All platforms have a minimum length of 120 m, so that during periods of very high traffic load—especially in the morning peak of work and school transport—three sets of multiple units can be coupled.

The subsequent stops in Heilbronn's city centre are Bahnhofsvorplatz (with change from EBO to BOStrab procedures and electrification system), Neckar Turm am Kurt-Schumacher-Platz, Rathaus, Harmonie, Friedensplatz, Finanzamt and Pfühlpark.

Directly after this station Stadtbahn services operate over a ramp to connect back to the Hohenlohe Railway with a reversal of safeworking procedures from BOStrab to EBO and of the electrification system.