NSB Class 71

The unit is based on the Swedish X2 designed by Kalmar Verkstad in the 1980s, and delivered from 1990 to the Swedish State Railways for use in their X 2000 high-speed intercity trains. Although the technology involved is similar, like spot-welded stainless steel car bodies, the Class 71 differs in several ways. First, the unit does not have a separate locomotive unit, but has the motors spread throughout the train, with one powered and one unpowered bogie in each car. The car bodies are totally different in layout, including the doors between bogies instead of at the end of the cars. In addition, the trains are pressure tight to increase comfort for passengers while passing through tunnels. They also have hydraulic couplers at the ends, which are hidden behind covers when not used. The Class 71 is also shorter, with only three cars, and does not have any tilting technology installed. The exterior design, especially the nose, is quite different. Norges Statsbaner later took order of 22 units of the Class 73, that is almost identical, but has four cars and tilting technology. Class 73's pantograph is pivoted in order to keep it centred under the catenary when the body tilts. Each train has a power output; this is an unusually high power to weight ratio for trains with that maximum speed. The units use the standard Norwegian voltage of . Up to four units can be run in multiple, creating 12-car (or 16-car after the upgrade) trains. However, the trains normally only operate as single or double units, limiting the length to eight cars. End cars are and weigh , while center cars are and weigh . The pantograph is located on the center car. Each unit has 168 seats, that are built modally so that the seating can be reconfigured. The sixteen units cost . During construction, the weight had increased from 149 to 170 tonnes; to reduce this to 158 tonnes, the original idea of step-free access was discontinued. Instead, a wheelchair lift was installed, but it proved not to work. The area around the doors are step-free from the platform, but within the trains steps must be taken to reach the seating area. The Class 71 is capable of speeds up to , compared to in the original. This speed was chosen to make it possible to get from Oslo Central Station to Oslo Airport, Gardermoen in less than 20 minutes. The signalling system ATC-2 is built for , and could not be adopted for much more than that. The three car units (resp. four car units) can only be separated at a railway workshop, and are never used in anything but their native car configuration. ==History==

When the Parliament of Norway decided to build Oslo Airport, Gardermoen, on 8 October 1992, they also decided to build a high-speed airport rail link from Oslo Central Station to the airport. This railway, the Gardermoen Line, was to be built and operated by a subsidiary of Norwegian State Railways, NSB Gardermobanen. To operate the railway they needed sixteen electric multiple units. The rebuilding created several challenges for Bombardier, since most of the components used in the class were no longer available. Significant components such as the car body and rectifiers had to be built by Bombardier based on abandoned production lines, and many of the original manufacturers for the interior have become defunct. From 2010, the Norwegian Rail School operates a simulator center for training motormen. It consists of six mock-ups of the Class 71 driver's cab, and is used both by the school and to train existing Airport Express Train drivers in exceptional circumstances. The simulators were built by Sydac and cost NOK 35 million. ==Incidents==

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. Several deaths have taken place on the route, but only one due to an accident. In 1999, an employee of the Norwegian National Rail Administration was killed after impact with a train; the authorities stated that the cause was due to the train operating at , instead of the temporarily reduced limit of . The company was fined for not informing the driver of the speed limit reduction. Several other deaths on the line have been classified as suicides, and so are not part of the accident statistics; they do however cause delays on all services for hours after the incidents take place. In 2000 and 2001, Flytoget experienced three derailments with empty trains at Gardermoen; one caused by the engineer falling asleep and two by the train passing a red signal. No more such accidents occurred after Automatic Train Control was installed in 2001. ==References==