Herrenknecht, based in Schwanau in the German state of Baden-Württemberg, manufactures tunnel boring machines. "Maintenance is essential for systems as complex as tunnel boring machines. If we manufacture them properly, we have no downtime and our job is much easier," explains Hugh O'Hagan, maintenance technician at Europe's largest infrastructure construction site in London. A rail link (called High Speed Two or HS2) for trains travelling at up to 360 km/h between the north of England and London is being built. Two tunnel boring machines (TBMs) from Herrenknecht are being used. Their reliability is thanks to, among others, the digital maintenance and servicing software AX Smartenance from Festo.