the extension in the northerly direction took place in several stages. it was extended to cottbuser platz on 31 july 1999, to siedlerheim on 13 november 2000, to riegelsberg süd on 24 september 2001 and to walpershofen/etzenhofen on 26 september 2009. construction of the riegelsberg süd–walpershofen/etzenhofen section, required the contribution of additional costs of around €630,000 per year (an amount that was until recently disputed) from the city of saarbrücken, the municipality of riegelsberg and indirectly from the saarland. clearing work was performed on the former route of the koller valley railway (lebach–völklingen railway) through walpershofen and dilsburg in january and february 2009, the railway overpass in the center of walpershofen was renewed in 2009/10 and the reactivation of heusweiler markt was largely completed in the summer of 2011. this stretch of track was inaugurated on 30 october 2011.