Owing to a shortage of frequencies, DB Netz AG was unable to use GSM-R communications for shunting in the region serving Frankfurt am Main’s central station, including the ICE depot at Frankfurt-Griesheim station. DB Netz commissioned HÖRMANN Kommunikation & Netze to carry out the structural work involved in making modifications. It took the fitters just 72 hours to modify 15 GSM-R mast sites, including aerial measurements and carrying out the proper final inspection procedures. This required the fitters to replace 20 aerials, including their supporting structures, while some aerials were removed and not replaced.