After the occasional long-distance passenger services had been withdrawn in the 1990s, the Murg Valley Railway was integrated into the network of the Karlsruhe Stadtbahn between 2002 and 2004.

At Freudenstadt, these meet the services of the Ortenau S-Bahn (OSB), operating over the Kinzig Valley Railway to Offenburg.

The construction of the railway line in the lower Murg valley accelerated the Industrial Revolution around the towns of Gaggenau and Gernsbach.

Further upstream a centre of paper production developed from the 1880s with the establishment of several factories, aided by the substantial resources of forests and water.

Initially the extension of the line as a horse-drawn railway was considered, but failed to proceed due to lack of funding.

Freudenstadt, which is situated high above the upper Murg valley, had in 1879 received a connection towards Stuttgart with the completion of the Gäu Railway, part of the Württemberg rail network.

Finally, the Freudenstadt Central Station–Freudenstadt Stadt–Baiersbronn section was adopted, with maximum gradients of up to 5.0 percent, as a rack railway using the Riggenbach-Klose system.

While the desire was expressed for a continuous Murg Valley Railway from Rastatt to Freudenstadt in Baden quite early, the state of Württemberg behaved rather negatively, as there was a fear that traffic from the northern Black Forest would migrate towards Karlsruhe, while at that time freight and passengers mainly travelled over the line to Stuttgart.

The founding of Deutsche Reichsbahn in 1920 overcame the conflicts of interest between Baden and Württemberg, leading to the missing intermediate section between Raumünzach and Klosterreichenbach finally being commissioned on 13 July 1928.

It was not until the advance of the front in September 1944 that several attacks by fighter-bombers and artillery caused damage and line closures, mainly affecting Rastatt station.

[9] In addition until the mid-1990s, some D-trains or InterRegio trains also ran on the line; these were important for the tourism from the Ruhr area to the northern Black Forest.

Preliminary proposals for the integration of Murg Valley Railway with the Karlsruhe Stadtbahn were developed in the early 1990s.

With the political support of the rural districts (Landkreis) of Rastatt and Freudenstadt, the Albtal-Verkehrs-Gesellschaft (Alb Valley Transport Company, AVG), leased the Murg Valley Railway from Deutsche Bahn until 2000 by lease and upgraded it in subsequent years for light rail operations.

The renovations included the electrification of the line on the 15 kV AC 16.7 Hz system, duplication between Kuppenheim and Bad Rotenfels, the construction or reconstruction of crossing loops in Hörden, Hilpertsau, Langenbrand, Raumünzach and Heselbach, the construction of 14 new stations and the upgrading the existing stations, replacement of the signal and safety systems and the rehabilitation of bridges and tunnels.

During the electrification of the tunnel sections, for the first time in Germany, overhead conductor rail was installed on open line.

[10] During the switch to Stadtbahn operation, the Murg Valley Railway was also integrated into the local transport association networks.

Services use rolling stock that is designed to use the Karlsruhe Stadtbahn's two electrical systems (15 kV AC 16.7 Hz and 750 v DC).

With its ten tunnels, eight bridges and steep sections, the line includes a series of solutions to technical challenges.

From here it leaves the plane and now runs along the Murg Valley through the halts of Bischweier and Bad Rotenfels Schloss.

South of Gaggenau station the line runs through the Mercedes-Benz factory, where in addition to a siding there is a halt for the company's employees.

Next, the line follows the Murg Valley to the south, past the halts of Ottenau and Hörden and finally reaches Gernsbach station, which has several tracks for freight and passenger transport.

After passing through the halt of Au and the Füllen and Hart tunnels, the line crosses the Murg again on a 127-metre-long bridge.

Next, the line runs on the eastern slope of the Murg, crossing a mountain spur through the Brach tunnel and reaches the imposing, 183 metre-long and 27 metre-high stone bridge over the Tennetschlucht.

South of Forbach, the line climbs to Schönmünzach station over a ten kilometre-long section that runs through an almost uninhabited, wooded area.

There are sidings for freight transport for the Kronospan company (Bischweier), Lang Recycling (Bad Rotenfels), Hörden timber (at Hörden operating station), Mercedes-Benz (Gaggenau), Mayr-Melnhof (Obertsrot), Smurfit Kappa (Weisenbach) and Stora Enso (Langenbrand).

In addition, until the early 1990s, there was a railway siding south of Weisenbach station that was several kilometres long and ran to the east of the Murg below Füllen tunnel.

The Rolling stock on the lower section of the Murg Valley Railway used to be based in Karlsruhe depot.

With the delivery of four railbuses of class VT 98.9 (798), capable of climbing steep grades to the Karlsruhe depot in 1956, the era of diesel operations began on the Murg Valley Railway.

However, a single V 100 could carry only haul 150 tonnes on the steep section, so services continuing from Baiersbronn needed two or three locomotives.

Since these were not allowed on the steep section, a change was required at Baiersbronn to class 627.0 diesel multiple units, which also operated in the Murg Valley from the 1980s.