Planning for a new line between Mannheim and Stuttgart (the two largest cities of Baden-Württemberg) began in 1970.
The railway lines that it replaced followed the terrain and followed rivers and valleys, resulting in steep gradients and sharp curves and thus not suitable for high-speed trains.
The 1973 federal transport plan incorporated the following minimum requirements for mixed traffic to accommodate heavy, slow goods trains and light fast passenger trains:
maximum grade of 1.25% (occasionally 2.0%)
curves with small superelevation and minimum radii of 4,800 to 7,000 metres
maximum line speed of 250 to 300 km/h
average construction costs of 30 to 50 million DM per kilometre
point-to-point connections between two railway junctions.

To fulfill these requirements, it was necessary to build a large number of structures such as bridges and tunnels.

In addition, a new technology had to be pursued: the Forst Tunnel is under the water table for its entire length and required a new water-diverting technology.
The Freudenstein Tunnel is through the porous rock strata, which flows as a result of heavy rains on the hillsides above it.
That geological feature required expensive safeguards, which were used for the first time.

A first planning statement for the Mannheim-Stuttgart route was published in 1974.
The Federal Ministry of Transport issued the building permit in 1975, and construction commenced in 1976.
More than 6,000 objections led to some route changes during the construction.
The construction of some sections was at times completely halted.
In seven places the protests of the nearby residents led to the building of cut and cover tunnels.
The longest tunnel of this kind was the Pfingstberg tunnel, which leads through a forest, a declared water protection zone, near Mannheim-Rheinau.

The route has a (comparatively low) maximum gradient of 12.5 per thousand with curves having a normal radius of 7,000 m and a minimum radius of 5,100 m. Rises are limited to a maximum of 80 mm.
The design speed for ICE trains is 300 km/h and in places limited to 250 km/h.
Cross-overs were provided for the planned operations mixing passenger and goods trains and for maintenance operations every five to seven kilometres.
Planning for the entire route was not resolved until 1985.
Planning for a new line between Mannheim and Stuttgart (the two largest cities of Baden-Württemberg) began in 1970. The railway lines that it replaced followed the terrain and followed rivers and valleys, resulting in steep gradients and sharp curves and thus not suitable for high-speed trains. The 1973 federal transport plan incorporated the following minimum requirements for mixed traffic to accommodate heavy, slow goods trains and light fast passenger trains:
maximum grade of 1.25% (occasionally 2.0%)
curves with small superelevation and minimum radii of 4,800 to 7,000 metres
maximum line speed of 250 to 300 km/h
average construction costs of 30 to 50 million DM per kilometre
point-to-point connections between two railway junctions.
To fulfill these requirements, it was necessary to build a large number of structures such as bridges and tunnels.
In addition, a new technology had to be pursued: the Forst Tunnel is under the water table for its entire length and required a new water-diverting technology. The Freudenstein Tunnel is through the porous rock strata, which flows as a result of heavy rains on the hillsides above it. That geological feature required expensive safeguards, which were used for the first time.
A first planning statement for the Mannheim-Stuttgart route was published in 1974. The Federal Ministry of Transport issued the building permit in 1975, and construction commenced in 1976. More than 6,000 objections led to some route changes during the construction. The construction of some sections was at times completely halted. In seven places the protests of the nearby residents led to the building of cut and cover tunnels. The longest tunnel of this kind was the Pfingstberg tunnel, which leads through a forest, a declared water protection zone, near Mannheim-Rheinau.
The route has a (comparatively low) maximum gradient of 12.5 per thousand with curves having a normal radius of 7,000 m and a minimum radius of 5,100 m. Rises are limited to a maximum of 80 mm. The design speed for ICE trains is 300 km/h and in places limited to 250 km/h. Cross-overs were provided for the planned operations mixing passenger and goods trains and for maintenance operations every five to seven kilometres. Planning for the entire route was not resolved until 1985.
Mannheim–Stuttgart high-speed railway