Norwegian State Railways (Norway)

To enhance the stability of continuous welded rail (CWR) tracks, frictional sleepers have been developed. The frictional sleepers are new types of sleepers with grooves on the bottom, and different bottom grooves improve lateral resistances at different magnitudes. In this study, single sleeper push test (SSPT) and its model with discrete element method (DEM) were carried out to confirm how much arrowhead groove frictional (AGF) sleeper increases the lateral resistance of ballasted track. The SSPTs were performed to confirm the lateral resistance results, and also to validate and calibrate the DEM models. With the validated models, the groove factors influencing the lateral resistances were studied, including groove sizes (depth, width), arrowhead groove direction and groove numbers. The reason of lateral resistance improvement was studied at mesoscopic level, including the ballast-sleeper contact numbers and contact force chains. Results show that applying the AGF sleeper is able to improve lateral resistance by 7–24%, and it can provide enough lateral resistance after reducing ballast shoulder width from 500 mm to 300 mm. The AGF sleeper can improve the sleeper-ballast interaction by increasing sleeper-ballast contact number. The study is helpful for frictional sleeper design, further improving track stability.

Recently, low-frequency instability has been observed in single-phase AC railway systems with modern railway vehicles, equiped with asynchronous motor and PWM line converter. Multiple approaches to study such a phenomenon have been introduced. One of the proposed impedance-based methods makes use of dq-decomposition of signals — a technique that is commonly used for three-phase systems. Such a representation results in a multiple-input multiple-output control system. In the present article, this complex control loop is studied using well-established control-theory techniques, such as the Nyquist criterion. A stability criterion is proposed and tested on a sample system.

Abstract The physiology of cracking, water uptake and quality of three sweet cherry cultivars that differ in their susceptibility to cracking were studied. Cracking appeared to be related more to the rate of water uptake than to the total amount of water that was accumulated. The less susceptible cultivars, "Ulster" and "Sam", appeared to obtain their cracking resistance by displaying a slower rate of water uptake and thereby having a greater period to accumulate the damaging quantities of water prior to cracking rather than by tolerating more water once absorbed. It is evident from this study that cultivaral differences in cracking are closely associated with indirect effects that the fruit osmotic potential and skin permeability have on the rates of water accumulation. Fruit from the more cracking-susceptible cultivar "Van" on F.12/1 rootstock accumulated more water and underwent more cracking than fruit from Colt rootstock. Fruit moisture content, fruit transpiration rates, fruit size and firmness, however, failed to help explain the cultivar difference in cracking propensity.

Bottomsets from glaciomarine deltas situated stratigraphically below and above the Weichselian maximum glaciation till at Skorgenes, western Norway, were tested for consolidation in an attempt to quantify the ice thickness at the time of deposition of the till. The value of the preconsolidation pressure in the lower unit (15 ± 1 MPa), indicates an ice thickness over the site of some 1350 ± 90 m. This is, however, only considered a minimum because values of preconsolidation pressures normally are lower than actual ice thickness would suggest due to incomplete drainage of the bed during consolidation. The estimated ice thickness indicates an ice surface some 400 m above the lower limit of the block field in the area, suggesting that this limit can not be used as a criterion for reconstructing the upper glacier surface for the Weichselian maximum glaciation in western Norway. Also, the nearest mountain peaks seemingly were completely ice covered, suggesting that no nunataks were present in that area.

In an attempt to assess whether exposure to electromagnetic fields on Norwegian railways induces brain tumors or leukemia, the authors conducted a nested case-control study of railway workers based on incident cases from the Cancer Registry of Norway in a cohort of 13,030 male Norwegian railway workers who had worked on either electric or non-electric railways. The cohort comprised railway line, outdoor station, and electricity workers. The case series comprised 39 men with brain tumors and 52 men with leukemia (follow-up, 1958-1990). Each case was matched on age with four or five controls selected from the same cohort. The exposure of each study subject to electric and magnetic fields was evaluated from cumulative exposure measures based on present measurements and historical data. Limited information on potential confounders such as creosote, solvents, and herbicides was also collected; information on whether the subject had smoked was obtained by interviews with the subjects or work colleagues. The case-control analysis showed that men employed on electric railways, compared with non-electric ones, had an odds ratio for leukemia of 0.70 (adjusted for smoking) and an odds ratio for brain tumor of 0.87. No significant trend was shown for exposure to either magnetic or electric fields. These results do not support an association between exposure to 16 2/3-Hertz electric or magnetic fields and the risk for leukemia or brain tumors.

Abstract Grazing Norwegian Red dairy cows were offered one of two roughage supplements ‘baled silage (S) or ryegrass (R)’ on an ad libitum basis for a limited period daily. A third group received concentrate (C). Milk and FCM yields were significantly (P<0.05) influenced by treatment (23.65 and 22.81, 23.20 and 22.05 and 22.58 and 22.73 kg d−1, for S, C and R, respectively). Milk composition was unaltered. The cattle offered ryegrass consumed significantly (P<0.05) more supplementary feed and less pasture, and spent less time grazing and more time ruminating than the other two groups. Cattle with high initial yields, despite higher intakes of both pasture and supplement, had reduced liveweight gains and a faster decline in milk production in comparison with low yielders.