## 3 Trackside Measurement through Field Instrumentation
### Field Measurement Result Comparison
Figure 9: Dynamic stability evaluation result comparison for concrete track types: (**a**) wheel load fluctuation, (**b**) derailment coefficient, (**c**) track support stiffness, and (**d**) rail stress. In the above calculation process for both ballasted and concrete track structures/types, the analysis dynamic stability performance evaluation results show that all 10 types of track structures, for both ballast and concrete structure types, meet the design specification requirements outlined in KR-C 14030. However, the difference between the range of results when comparing the ballasted versus the concrete structure types was clearly different, with the exception of the derailment coefficient, where for both classifications of tracks, the range was safely within 0.1-0.3. The minimal variance can be seen between the different track types/structures in between the ballasted and concrete track types, it was shown that for ballasted track structures, wheel load fluctuation, track support stiffness, and stress values were higher than those for the concrete track types. Ballasted tracks Type 1 and 2 particularly stood out in that the values were nearing the safety limit (\(\leq\)1.2, referring to Table 1). As far as the inter-comparison between the track classifications is concerned, some types showed relatively high slopes of change in their performance in accordance with increasing speed, in particular for the concrete track types. Ballasted track structures, while having results higher in value, show in general consistent performance throughout the increasing speed ranges, but track Types 1 and 2 show \begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{3}{*}{\
\begin{tabular}{c} **Railway** \\ **Structures** \\ \end{tabular} } & \multirow{3}{*}{
\begin{tabular}{c} **Speed** \\ **(km/h)** \\ \end{tabular} } & \multicolumn{3}{c}{**Track Performance and Dynamic Stability per vehicle speed**} \\ \cline{3-6}  & & **Wheel Load** & **Deraliment** & **Track Support** & **Stress** \\  & & **Fluctuation (\({}^{\text{(1)}}\))** & **Coefficient (\({}^{\text{(2)}}\))** & **Stiffness (kN/mm)** & **(MPa)** \\ \hline \multirow{6}{*}{\(\text{Type 1}\)} & 120–130 & 0.04 & 0.13 & 65.38 & 23.78 \\ \cline{2-6}  & 130–140 & 0.02 & 0.15 & 66.27 & 28.45 \\ \cline{2-6}  & 140–150 & 0.03 & 0.14 & 66.35 & 38.71 \\ \cline{2-6}  & 150–160 & 0.04 & 0.13 & 61.86 & 42.42 \\ \cline{2-6}  & 160–170 & 0.05 & 0.17 & 59.20 & 48.21 \\ \hline \multirow{6}{*}{\(\text{Type 2}\)} & 120–130 & 0.05 & 0.17 & 72.44 & 36.75 \\ \cline{2-6}  & 130–140 & 0.06 & 0.22 & 70.92 & 38.21 \\ \cline{2-6}  & 140–150 & 0.05 & 0.19 & 64.42 & 38.65 \\ \cline{2-6}  & 150–160 & 0.02 & 0.24 & 69.72 & 40.82 \\ \cline{2-6}  & 160–170 & 0.01 & 0.23 & 74.71 & 39.52 \\ \hline \multirow{6}{*}{\(\text{Type 3}\)} & 120–130 & 0.03 & 0.26 & 84.50 & 35.48 \\ \cline{2-6}  & 130–140 & 0.03 & 0.21 & 95.13 & 36.75 \\ \cline{2-6}  & 140–150 & 0.01 & 0.20 & 54.02 & 40.14 \\ \cline{2-6}  & 150–160 & 0.03 & 0.22 & 54.95 & 46.08 \\ \cline{2-6}  & 160–170 & 0.08 & 0.21 & 59.75 & 41.82 \\ \hline \multirow{6}{*}{\(\text{Type 4}\)} & 120–130 & 0.03 & 0.11 & 97.27 & 28.75 \\ \cline{2-6}  & 130–140 & 0.04 & 0.13 & 86.46 & 32.42 \\ \cline{2-6}  & 140–150 & 0.03 & 0.15 & 96.30 & 31.27 \\ \cline{2-6}  & 150–160 & 0.01 & 0.16 & 89.09 & 33.72 \\ \cline{2-6}  & 160–170 & 0.06 & 0.18 & 98.69 & 34.74 \\ \hline \multirow{6}{*}{\(\text{Type 5}\)} & 120–130 & 0.03 & 0.15 & 80.58 & 38.61 \\ \cline{2-6}  & 130–140 & 0.04 & 0.17 & 89.25 & 39.57 \\ \cline{1-1} \cline{2-6}  & 140–150 & 0.04 & 0.16 & 93.45 & 42.81 \\ \cline{1-1} \cline{2-6}  & 150–160 & 0.02 & 0.21 & 78.68 & 40.63 \\ \cline{1-1} \cline{2-6}  & 160–170 & 0.06 & 0.20 & 74.40 & 41.52 \\ \hline \end{tabular}
\end{table} 
Table 10: Calculation result of track performance and dynamic Stability according to railway structures per vehicle speed ranges (concrete track types). an increasing trend of derailment coefficient, and Type 1 shows a higher increasing trend with the stress parameter.