In space Christmas, it became clear that the huge Follobanen project has a problem, and must remain closed indefinitely. Managing director of Bane Nor Gorm Frimannslund has stated that the target for a new opening is in February. Aftenposten writes that the best scenario is for the track to open on 1 February. The railway line has a price tag of NOK 36.8 billion and took 13 years to build. On both 20 December and 23 December, a junction house caught fire in Ski. A fault with the system for return current and grounding is the reason why the track must remain closed. Points to weaknesses Bane Nor wanted an additional assessment of the system, and in October received a report from the consultancy company Norconsult which pointed to weaknesses. Now the much-discussed report has been made public. It was in a crisis meeting with transport minister Jon-Ivar Nygård that it became known to the general public that Norconsult had prepared such a report. Project director for Follobanen Per David Borenstein. Photo: Rodrigo Freitas / NTB In the press release Bane Nor wrote that the main goal of the report was to get an independent assessment of whether return current from the Blix tunnel, Østfold line and Konshavn tunnel would affect the signaling system at Oslo S when Follobanen opens. In addition, Norconsult was asked to carry out an independent assessment of the documentation of the chosen solution for return current. “In Follobanen, the general contractor had chosen a technical solution that was within our technical regulations, but it was new to us. That is why we asked for an independent assessment that would go through the supplier’s calculations”, writes Bane Nor in the press release. – We work on a risk-based basis, which means that various risks are continuously and continuously identified in the project, which must be looked at more closely. They are classified systematically in a risk register, explains Per David Borenstein in the press release. Make several recommendations In the report, there was criticism of the system chosen by the subcontractor Cowi, but in the end the choice fell on this system nonetheless. – The chosen solution for Cowi is consistent with Bane Nor’s technical regulations, Bane Nor wrote in a press release on Friday. In the report to Norconsult, the consulting firm has made a total of nine recommendations for Bane Nor. Norconsult recommends, among other things, that it should be “verified with better calculation and/or measurement that current in cable shields when earthing at both ends does not lead to unacceptable thermal stress on the cable”. Recommendations from Norconsult Recommendation 1: In the period after commissioning, one should monitor the stability of the single insulated track fields on the section. If they show signs of being affected by disturbances from return currents, measures should be considered. Current measures are:• Improvements in the return circuit so that less return current goes into the earthed running rail.• Use of single insulated track section type 2 Based on the assessments in this report, however, no such effects are expected. Recommendation 2: Feed to the Kongshavn tunnel should be changed.• Suction transformer 4.1 should be removed.• Normal feed to the Kongshavn tunnel should be from Oslo junction house via KL-kiosk 4. It is recommended here to make both of these changes, but they can be carried out independently of each other if necessary. Recommendation 3: Longitudinal grounding conductors with 120 mm2 aluminum in cable duct which are connected to the other return circuit at only one end should be inspected regularly, especially after high current short circuits. It can be considered to improve by connecting the “open” ends of the longitudinal earth conductors in the cable duct to the nearest earthed running rail. Recommendation 4: It should be verified with better calculation and/or measurement that current in cable shields at grounding at both ends does not lead to unacceptable thermal stress on the cable. Recommendation 5: Measuring points are recommended for verifying the calculated current distribution between conductors in the return circuit when measuring. Measurement should be done in a test situation with a known total current load for the circuit. Recommendation 6: Earthing diagram UOS-10-R-85229 and UOS-10-R-85239 should be updated so that the connection between the longitudinal earth conductor in the cable channel and the running rails is removed at km 1,965 and km2, 000 for respectively tracks FB1 and FB2. Recommendation 7: Connections with C-press between longitudinal earth conductors in aluminum and leveling connections in cups should be monitored, especially in the first period. If there are signs of corrosion at the contact points, the couplings should be replaced. Recommendation 8: Connections between busbars/filter impedances and earth conductors should be shown both in return circuit diagrams and in earthing plans. The earthing plans UOS-10-R-85228, UOS-10-R-85229 and UOS-10-R-85239, and the return circuit diagram UOS-10-R-86122, should show such interconnections between the longitudinal earth conductor and filter impedances in the case of double-insulated track field. Recommendation 9: The return circuit diagram UFB-30-R-65700 revision 02C should be updated with corrected direction indication for detail A and detail D. Norconsult also writes that there are “other potential sources of unacceptable influence on protection systems”, but that such other potential sources of error have not been assessed further in this report. Will not say who has had access to the report A question related to the report has been who has had access to it. Bane Nor CEO Gorm Frimannslund has said that no one told him about the risk before the track was opened on 11 December. The chairman of Bane Nor, Cato Hellesjø, has said that he became aware of the report on Tuesday this week. He believes that the information about the risk should not only reach the CEO, but also the board. Cato Hellesjø is chairman of Bane Nor, and would have liked to have known that the professional community had found weaknesses with the Folloban before it opened. Photo: Håkon Mosvold Larsen / NTB news has on several occasions asked Bane Nor who got and has read the report. news has not received an answer to this. Nor does the press release give an answer as to who was allowed to and has read the report. SV: Pulverization of responsibility The Socialist Left Party believes “pulverization of responsibility and a sea of subcontractors” characterizes Follobanen. – I think it is unsustainable that the management in Bane Nor has not been aware of the return stream criticism. It is their responsibility as a tenant, says Mona Fagerås in the Transport and Communications Committee for SV. She says that it seems that the pulverization of responsibility rises in line with the number of directors. – Now the Minister of Transport must clean up and show action. We cannot have it like this in Norwegian railways, she says. Transport Minister Jon-Ivar Nygård wants an external review of the case. – Information has come to light that worries me. There has been uncertainty about the solution that has been chosen when it comes to return current and grounding, he said on Tuesday.
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Bane Nor publishes the report from Norconsult – news Norway – Overview of news from different parts of the country
