Where and When Snow Comes Off a Moving Train

The snowfall from a snow-laden (from a snowfall) train is somewhat predictable—and so can be somewhat controlled, suggests this study:

“Studies of Snow-Dropping from a Train on a Turnout due to Dynamic Excitations,” Tiia-Riikka Loponen, Pekka Salmenperä, Heikki Luomala, and Antti Nurmikolu, Journal of Cold Regions Engineering, vol. 32, no. 2, June 2018. The authors, at Tampere University of Technology, Finland, report:

Snow accumulated on a train underframe may detach itself in places where rail discontinuity causes an excitation to the train. In turnout areas, this may cause serious problems when snow buildup from beneath the rolling stock drops into the gap between the switch blade and the stock rail and disrupts the turnout operation….

Based on the research results, it can be said that turnouts are a considerable cause of vibration in rolling stock. Should snow accumulate on the rolling stock and detach itself exactly due to excitation originating from a point of discontinuity of the rail, the snow is likely to drop at the location of a turnout. It was clearly observed in 2009–2010 that snow tends to drop from rolling stock in turnout areas; this means that, in adverse weather conditions, the acceleration levels created at turnout locations are sufficient to drop snow from rolling stock. The acceleration levels established by the measurements may therefore be used to develop methods to drop the snow, such as introducing intentional points of discontinuity in the rail to drop snow from the rolling stock.

(Thanks to Tom Gill for bringing this to our attention.)