## 4 Results and Discussion
### Total Spring Constant of the FEM Models and Track Calculation Result  
The total spring constant of track according to finite element analysis result is calculated and compared with the value derived from field measurement (shown in Tables 10 and 11). To calculate total spring constant of track in ballasted track, Equation (5) was used. In addition, using wheel load and vertical rail displacement from field measurement, total spring constant of track is calculated in both ballasted track and concrete tracks (as is shown from Tables 12 and 13 below). The total spring constant of the respective track types, both 3D models and the real track sites, are outlined in a graph format in Figure 10.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Train Speed** & **Wheel Load** & **Vertical Rail Displacement** & **Total Spring Constant of Track** \\
**(km/h)** & **(kN)** & **(mm)** & **(kN/mm)** \\ \hline
85 & 139.32 & 0.697 & 199.88 \\
95 & 141.36 & 0.706 & 200.23 \\
155 & 148.75 & 0.749 & 198.59 \\
185 & 152.75 & 0.760 & 200.98 \\
195 & 154.11 & 0.767 & 200.93 \\
205 & 155.47 & 0.772 & 204.38 \\ \hline \hline \end{tabular}
\end{table}
Table 10: Total spring constant of ballasted track (FEM).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Train Speed** & **Wheel Load** & **Vertical Rail Displacement** & **Total Spring Constant of Track** \\
**(km/h)** & **(kN)** & **(mm)** & **(kN/mm)** \\ \hline
85 & 94.21 & 1.05 & 89.72 \\
95 & 101.9 & 1.09 & 93.48 \\
155 & 97.89 & 1.07 & 91.48 \\
185 & 125.3 & 1.11 & 112.88 \\
195 & 124.3 & 1.18 & 105.33 \\
205 & 123.2 & 1.13 & 109.02 \\ \hline \hline \end{tabular}
\end{table}
Table 12: Total spring constant of ballasted track (Field measurement).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & & **Wheel Load (kN)** & \\ \cline{2-3}
**Speed (km/h)** & **Concrete and Ballasted FEM** & **Ballasted** & **Concrete** \\
**(Eisenmann DAF \(\times\) x** & **Track Field** & **Track Field** \\
**Static Load \((85\) kN))** & **Measurement** & **Measurement** \\ \hline
85 & 139.32 & 94.21 & 89.34 \\
95 & 141.36 & 101.9 & 87.41 \\
155 & 148.75 & 97.89 & 88.24 \\
185 & 152.75 & 125.3 & 95.82 \\
195 & 154.11 & 124.3 & 98.1 \\
205 & 155.47 & 123.2 & 101.3 \\ \hline \hline \end{tabular}
\end{table}
Table 9: Ballasted track field measurement result summary.  
Total spring constant comparison results showed the following results. Between the finite element tracks, concrete track total spring constant is about 61% of the ballasted track. Between the real track sites, the concrete track total spring constant is about 85% of the ballasted track. Between the finite element track to the real track site comparisons, the actual ballasted track is 50% compared to the 3D model version, and for the 68% concrete track site comparison. As a result of overall comparison analysis, it is judged that the currently applied dynamic factor application method will bring about a deviation between the track types. This indicates that the dynamic factor calculation methods should be reconsidered to derive a separate application method that considers each track type's stiffness properties due to the evident differences.