## 6 Evaluation of the Results  
The created database contains signals generated at the laboratory which in the best way possible reflect the real ones, that can be observed during wheel detector operation in the real-life conditions. The wheel signatures were gathered based on especially prepared samples of wheels, created on the basis of the real profiles. To a certain extent, it is possible to compare the obtained signals with the real ones registered in the field. The main problem with such a comparison is that generally during measurements on site it is difficult or very often even impossible to identify the real wheel conditions, their real dimensions and their lateral position in relation to the rail head. This is the main reason why the measurements on site are not sufficient to form the basis for development. An example of the internal signals of the wheel detector registered in the field during the passage of trains (Hyundai Rotem EMU, R-Train, wheels diameter 840 mm (new), 780 mm minimum) is presented in Figure 21. The signal of wheels, pulse and continuous disturbances registered in respect of seven trains are presented in Figure 21A. The signals of one train are presented in Figure 21B). It can be seen that the train is composed of six cars with two bogies per car and two axles per bogie. The signals were registered at the sampling rate of 3 ksps, range 0-3 V and trigger level set on 1 V.  
The signals were gathered in one of the installations in metro, where high electromagnetic disturbances were observed. The comparison of the wheel signature generated for k16 wheel (\(\varphi\)820 mm) and the position p0 (file: S60_k16_p0_1.csv, u1 lab and u2 lab) and  
Figure 21: (**A**) The real signals of a trains passages; (**B**) A single train signals zoomed. Figure 20: Structure of folders in the database. the one wheel of the train (u1 real, u2 real) is shown in Figure 21. The correlation factors are presented in Table 7.  
The train was traveling at the speed of 80 km/h, what was estimated based on the time between impulses coming from axles in the bogie and confirmed by the time between impulses coming from axles of the following coaches (Table 8). The 80 km/h is also the operational speed on the line where the signals were recorded and as it was precisely controlled by ATO system it is assumed to be estimated correctly. The generated wheel signature presented in Figure 22 (u11 ab, u2 lab) was scaled to the estimated speed according to method described in the paper and it can be seen that its shape is very close to the real one. Small deviations are caused by the differences in the wheel profiles and most probably by the position of the wheel on the rail. The dimensions of samples of wheels used for database creation represent the boundary conditions, as the real ones may have not only such dimensions but also any dimension in between them. The lateral position of a wheel during the train passage is unpredictable and may reach any value between 0 (p\({}_{0}\)) and 60 mm (p\({}_{1}\)), defined by the standard. The character of the pulse disturbance added to the signatures was also prepared based on the signals recorded in the field. In reality such a disturbance is typically an effect \begin{table}
\begin{tabular}{c c c} \hline
**Wheel** & **u1** & **u2** \\ \hline
1 & 0.9994 & 0.9983 \\
2 & 0.9910 & 0.9986 \\
3 & 0.9994 & 0.9987 \\
4 & 0.9963 & 0.9987 \\
5 & 0.9961 & 0.9983 \\
6 & 0.9955 & 0.9982 \\ \hline \end{tabular}
\end{table} 
Table 7: The correlation factor of signals, after resampling and removing the offset (wheels from different bogies and different trains). \begin{table}
\begin{tabular}{c c c} \hline
**Wheel** & **Distance** & **Estimated Speed [km/h]** \\ \hline Axles distance in a bogie & 2150 * & 79.79 \\ Axles of the following coaches & & \\ based on coach length & 22,000 & 81.64 \\ \hline \end{tabular}  
* the exact dimension is unknown, the average value of this dimension for similar type of rolling stock was used.  
\end{table} 
Table 8: The estimated speed of the train.