# Method for Determining the Susceptibility of the Track
## 2 Experimental Testing on a Real Object
### Vertical Stiffness Measurements of Straight Track  
The loads on the individual axles of the wheelsets are shown in Table 1.  
The train, which was moving at 5 km/h, had a structure like the one in Figure 1.  
There are 11 measuring points distributed in the track as shown in Figure 2.  
Figure 1: Composition of the measuring train. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multicolumn{2}{c}{**Gross Axle Load of the Two-Axle Platforms, N**} \\ \cline{2-4}  & **Platform** & **I Axle** & **II Axle** \\ \hline
1 & 400,000 & 208,000 & 192,000 \\ \hline
2 & 217,000 & 83,000 & 134,000 \\ \hline
3 & 347,000 & 150,000 & 197,000 \\ \hline
4 & 366,000 & 155,000 & 211,000 \\ \hline
5 & 124,000 & 62,000 & 62,000 \\ \hline \multicolumn{4}{c}{**Gross load capacity of a coal truck with bogies 25 T N**} \\ \cline{2-4}  & **coalminer, N** & **I \(Bogie\), N** & **II \(Bogie\), N** \\ \hline
6 & 387,000 & 193,500 & 193,500 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Axle loads of individual wheelsets. Figure 2: Position of measuring points. The points were positioned in such a way as to eliminate the influence of deflection at neighboring measurement points. The measurement train passing at 5 km/h caused deflection of the track at various measurement points. An example of track deflection is shown in Figure 3.  
Five runs were made, resulting in five deflections at each measurement point. Mean deflection values and standard deviation were determined for these quantities. These results are shown in Table 2. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multicolumn{2}{c}{\(P\)\(\cdot\)\(10^{4}\) N} & \multicolumn{10}{c}{Mean Values \(z\)\(\cdot\)\(10^{-4}\) m} \\ \cline{2-13}
**on a Wheel** & **p-p.1** & **p.p.2** & **p.p.3** & **p.p.4** & **p.p.5** & **p.p.6** & **p.p.7** & **p.p.8** & **p.p.9** & **p.p.10** & **p.p.11** \\ \hline
3.1 & 8.86 & 5.88 & 5.24 & 5.60 & 3.90 & 5.22 & 6.04 & 8.16 & 16.42 & 6.82 & 3.88 \\
3.1 & 8.18 & 5.83 & 5.18 & 5.30 & 3.72 & 4.76 & 6.28 & 7.90 & 15.44 & 6.86 & 3.45 \\
4.15 & 10.28 & 7.53 & 6.98 & 7.34 & 5.54 & 6.90 & 8.16 & 11.28 & 17.76 & 9.22 & 4.83 \\
6.7 & 11.84 & 7.99 & 7.68 & 8.22 & 6.36 & 7.58 & 9.54 & 12.58 & 18.82 & 10.50 & 5.28 \\
7.5 & 12.68 & 8.59 & 7.62 & 8.82 & 6.30 & 8.52 & 9.10 & 12.02 & 19.28 & 10.36 & 6.38 \\
7.75 & 12.88 & 9.05 & 7.96 & 9.24 & 6.76 & 8.98 & 10.04 & 12.42 & 19.19 & 11.18 & 6.88 \\
9.6 & 13.70 & 9.13 & 9.30 & 9.62 & 7.44 & 9.40 & 11.08 & 13.58 & 20.00 & 11.88 & 7.08 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Rail deflections. Figure 3: Example of track deflection. The magnitudes of the standard deviations do not exceed 12% of the mean value. The correlation coefficient between force and deflection was determined for the individual measurement points. This coefficient is given in Table 3.  
The value of this coefficient allows the function P (z) to be approximated by a straight line. The approximation does not take into account the results of the 3.1\(\cdot\)10\({}^{4}\) N load, because, as can be seen from Figure 4, the deflection of the rail from axis 5 II is influenced by the load from axis 5 II and the load from the axle of the coal carriage. In addition, since the stiffness characteristics of the track with subgrade are linear, there is a danger of being at the lower end of the characteristics with this load, where the stiffness is less than that determined. The average value of the resulting stiffness coefficient of the pavement with subgrade per rail is 1.54\(\cdot\)10\({}^{8}\) N/m, and the coefficient of variation is 15%.