# Modernization of Heavy Loaded Tram Radial Effect on Noise and Vibration
## 3 Noise and Vibration Effects of Modernisation
### Experimental Measurements on the Old Bridge  
Measurement of noise conditions and vibration levels on the Old Bridge was implemented in partly cloudy weather and at a temperature of 24-28 \({}^{\circ}\)C and the southern, variable, 5-12 m/s wind. The first part of the Petrzalka tram project (Figure 13) included a proposal for building a 2.4 km long double-track line from the intersection of Stur and Jesensky Streets, through Safarik Square and Old Bridge to the intersection of Jantar and Rusovce Roads. Part of this project was also the reconstruction of the Old Bridge, including the replacement of the original bridge structure with a new load-bearing steel horizontal structure. On the bridge in question, the track was designed with a dual gauge of 1000 and 1435 mm with four rails in each direction. Both gauges are available along their entire length with the symmetrical track layout. The exception is switches that allow passage and turning only for a gauge of 1000 mm. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Bratislava–Stür Street**} & \multicolumn{3}{c}{**B1 Vy**} & \multicolumn{3}{c}{**B1 Vz**} \\ \hline \multicolumn{2}{c}{**Measurement Number/Track/Direction/Type**} & \multicolumn{1}{c}{**Start/Elapsed Time (s)**} & \(\mathbf{v}_{max}\) & \(\mathbf{v}_{min}\) & \(\mathbf{v}_{rms}\) & \(\mathbf{v}_{max}\) & \(\mathbf{v}_{min}\) & \(\mathbf{v}_{rms}\) \\ \multicolumn{2}{c}{} & \multicolumn{1}{c}{**(mm/s)**} & \multicolumn{1}{c}{**(mm/s)**} & \multicolumn{1}{c}{**(mm/s)**} & \multicolumn{1}{c}{**(mm/s)**} & \multicolumn{1}{c}{**(mm/s)**} & \multicolumn{1}{c}{**(mm/s)**} & \multicolumn{1}{c}{**(mm/s)**} \\ \hline
1/K1/CE/N & 10:26/08 & 10.05 & \(-9.11\) & 1.57 & 11.27 & \(-10.37\) & 1.84 \\
2/K1 + K2/CE.PE/N & 10:30/11 & 7.93 & \(-7.86\) & 1.25 & 9.67 & \(-11.04\) & 1.91 \\
3/K1/CE/N & 10:33/12 & 20.31 & \(-20.40\) & 3.43 & 8.29 & \(-9.82\) & 1.55 \\
4/K1/CE/N & 10:37/10 & 17.40 & \(-19.56\) & 3.21 & 13.79 & \(-11.10\) & 1.58 \\
5/K2/PE/N & 10:42/13 & 23.64 & \(-19.85\) & 3.26 & 9.21 & \(-12.16\) & 1.72 \\
6/K1/CE/O & 10:48/13 & 17.05 & \(-18.24\) & 1.96 & 11.65 & \(-12.97\) & 1.37 \\
7/K1/CE/O & 10:58/12 & 25.31 & \(-20.21\) & 3.31 & 8.33 & \(-9.94\) & 1.76 \\
8/K2/PE/O & 11:01/10 & 20.97 & \(-19.39\) & 3.14 & 8.91 & \(-10.80\) & 1.73 \\
9/K1/CE/O & 11:07/09 & 10.24 & \(-8.34\) & 1.87 & 9.24 & \(-8.78\) & 1.41 \\
10/K2/PE/N & 11:11/12 & 26.24 & \(-20.38\) & 3.09 & 10.09 & \(-10.85\) & 1.90 \\
11/K1/CE/N & 11:13/11 & 18.17 & \(-18.67\) & 2.95 & 16.35 & \(-11.87\) & 2.29 \\
12/K1/CE/O & 11:18/10 & 8.66 & \(-9.96\) & 1.90 & 8.77 & \(-8.12\) & 1.29 \\ \hline \hline \end{tabular} O, N: old type of tram, new type of tram; CE: direction to Centre; PE: direction to Petrzalka.  
\end{table} 
Table 4: Amplitude characteristics from vibration velocity time records at points **B1 Vz** and **B1 Vy**. Figure 11: Total signal waveform of vibration velocity \(v(t)\). Figure 10: Vibration velocity time history \(v(t)\) and power spectral density \(G_{ii}\) of the vibration velocity recording for measurements for old types of trans. The new load-bearing steel structure of the bridge is a welded truss rhombic system. Unlike the original bridge structure, the sidewalks for pedestrians and cyclists were widened to 4.5 m on both sides of the bridge. Above pillars no. 4 and no. 5, viewing platforms were designed (Figure 14). The middle part of the bridge with a railway track placed in a concrete roadway is used exclusively for tram transport and rescue and safety units. The tram superstructure on the bridge is designed as a ballastless track with contactless rails, using Rie0R2 (for 1000 mm gauge) and Rie67R1 (for 1435 mm gauge) groove rails, equipped with a simple, flexible compensated catenary. Engineering networks (water supply, gas pipeline, high-voltage cables, and optical cables) are led in the space under the construction of the tram line. As part of the bridge reconstruction, two original pillars are used to construct the bridge structure.