In February 2008, DB AG called Europe-wide tenders for the preliminary design and approval planning. In December 2008, Deutsche Bahn AG initiated the planning approval for a 13 km-long section between Frankfurt Stadion station and the municipal limits of Mörfelden and Erzhausen. This section included an upgrade of the existing Riedbahn to four tracks and the construction of an island platform in Zeppelinheim station. The section was discussed at a public hearing and published in 2009. Deutsche Bahn expected in July 2010 that the planning approval decision would be made at the beginning of 2011. After some changes to the plan, the planning documents for the section were rewritten in September 2010. At the end of July 2017, this planning approval procedure was terminated at the request of DB Netz AG.
