The sister trains in service with NSB were prone to technical failures, since they have to operate on hundred-year-old infrastructure on cross-mountain services. The Class 71 has more lenient operating conditions thanks to better infrastructure, and therefore has not been prone to as much malfunction. The only incident to ground all the Class 71 trains occurred on 17 June 2000, after a Class 73-train operated by NSB derailed at Nelaug Station owing to stress on the axles. The Oslo Airport Express Trains were back in service the next day, while the 73-series had to wait another month before returning to service. On 24 January 2004, a Class 71 unit had to be taken out of service due to smoke from a stressed bearing, causing the replacement of the bearings on all units within days.