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Show p. = 1/ 5. According to Equation ( VII) in this case the runout distance in the horizontal area of the rail station free from obstacles will be s~ 45 m. After impact of the avalanche on the train it must have dammed up until the tipping force ( 850 kg/ m2 for the locomotive) was generated, and in so doing, according to Equation ( 17), its velocity was reduced from 13.5 to 9 m/ sec. Before the impact the kinetic energy per cubic meter of avalanche snow amounted to y . v2 / 2g = 1350 kg- m/ m3; overturning the locomotive consumed the kinetic energy of about 20 m3 of avalanche snow. The damming produced in this way also caused a reduction in velocity of the following avalanche snow of the order of magnitude indicated above. To push forward the overturned locomotive a pressure of about 400 kg/ m2 is necessary according to Section I. From the momentum equation P ~ Y/ g ( v Av) the velocity loss brought about in this manner is A v = 3.3 m/ sec. For the remaining velocity of 5.7 m/ sec Equation ( VII), with p. = 1/ 5, gives the run out distance s ~ 8 m. The above calculated results are in agreement with the observations ( Section I). C. Swiss Experience Taking everything into consideration, investigation of the utilizeable data from the 1951 catastrophe leads to forces of a similar order of magnitude to those which have been established in the 1954 catastrophe in the Vorarlberg ( see Section I). For this reason in the following only a few typical situations are discussed in more detail which reveal the effect of significantly greater forces or which make possible a check of particular calculations. A difference exists compared with the circumstances in the Vorarlberg; in the Swiss catastrophies, the terrain, after a relatively short slope of slight inclination, usually climbed through a steep, partly rocky zone, up to the usually high lying release zone. The steep avalanche paths often caused important, downward acting thrust forces [ see the comment on Equation ( IX) ] ; this has been observed for example at Vals and Andermatt. a) Andermatt 1951 [ ll] Concerning the surface avalanche which ran from the Kirchberg zone of defense structures. h = 2.2 m, Y = 150 kg/ m3, tyQ = 34°, t m = 24°, slope of the valley floor ~ 5% (^ u~ 3°), p. = Y/ 2000 Eq. ( V •): hu = 2.45 m ( III ): v = 20.5 m/ sec ( VIII): p = 4000 kg/ m2 ( 27' ): Pressure on telephone poles 20 cm in diameter P = 625 kg/ m 52 |