The single track section of the Nidder Valley Railway branches off from the Main-Weser Railway at Bad Vilbel station and turns to the east shortly after the northern exit from the station, crosses the Nidda and shortly later reaches the halt of Bad Vilbel-Gronau.

After Niederdorfelden station, which is a passing place, the line runs through the Büdesheim Tunnel between the municipalities of Schöneck and Nidderau.

Immediately after the tunnel, the line passes through the Nidderwiesen nature reserve and the edge of the town of Nidderau is soon reached at Windecken.

It is now operated by DB Regio Mitte as timetable route 634 on behalf of the FVV's successor, the Rhein-Main-Verkehrsverbund (Rhine-Main transport association, RMV), as its line 34.

Almost all of the Regionalbahn services on weekdays and about two thirds on Saturdays run to Frankfurt (Main) Hauptbahnhof, while the rest begin and end in Bad Vilbel.

In addition, with the commencement of the summer timetable of 2008, the maximum speed of trains was increased from 60 to 80 km/h and the interval between services was shortened on weekdays.

According to a local newspaper from the Wetteraukreis, RMV's deputy chairman of the supervisory board reported that an additional 260,000 train-kilometres would be provided on the line during this period.

Furthermore, all halts and platforms in the stations of Nidderau and Stockheim have been rebuilt and the exit height for the double-deck cars has been raised to 76 centimetres.

The explanation given by the RMV emphasised the cost of operating diesel locomotive-hauled double-deck sets in the peak periods; this led to plans to upgrade the line.

[3] The Nidder Valley Railway was operated at the end of the 1990s in the peak hour with locomotive-hauled trains of Silberling coaches (n-Wagen) and in the off-peak with class 628 diesel multiple units.

In parallel selective upgrade measures (the installation of crossing tracks at stations, two-track sections) would make possible the intensification of services.