Experimental determination of longitudinal forces in front of braking train

Abstract

The number of regularities detected in the experiments described by the author confirms that, despite of the differences in operating conditions between the middle of the 20th century and the present days, the methods of research and assessment of obtained results are still relevant.Features of the superstructure and track operation at the initial stage of introduction of the welded rails and continuously welded rail strings on the railways of the USSR are examined. It is demonstrated that axial displacement forces are occurred during the train movement, which are one of the most dangerous processes taking place in the track during the rolling stock movement. Axial displacement forces are manifested in the axial displacement of rails on the sleepers or displacement of rails with sleepers on the ballast. Knowledge of axial forces resulted from displacement of one rail line or the entire track is required for competent planning of installation and operation of the jointed rail track and continuously welded rail track, especially in the conditions of the Urals and Siberia. Methods and experimental results are provided for determination of additional axial forces acting in the track at the spike fastening and the individual intermediate fastening in front of braking train at the experimental sections of the continuously welded rail track in severe climatic conditions of the West-Siberian railway, where the annual fluctuations of therail temperature amount to 110°C.The following conclusions are made based on the analysis of the experiment results and experience of operation of the continuously welded rail strings: • no additional axial forces in front of braking train were detected in the continuously welded rail strings of the thermalstressed type without any release of thermal stresses on the independent fixation; • experiment confirmed possibility of installation and normal operation of continuously welded rail track on the entire network of railways of the Ministry of Transportation of the USSR; • recent wide introduction of trains of 7,100 t, combined trains of 12,600 and 14,200 tons require special attention to parameters of interaction of track and trains.

Keywords

• railway track
• wooden and reinforced concrete sleepers
• welded rails 50, 75 and 100 m long
• string truck
• strings of welded rails
• continuous welded rail track
• track displacement
• displacement forces
• braking train
• additional longitudinal forces