## 2 Measurement Campaign for the Bridge, Tunnel and Surface Lines  
A unique measurement campaign has been performed by the Federal Institute of Material Research and Testing (BAM) on a 3 km long section of the German high-speed line Hannover-Wurzburg [2]. Vehicle, track and ground vibrations have been measured simultaneously at a tunnel (the Muhlberg tunnel), a 45 m long box-girder concrete bridge and a conventional ballasted surface track (Figure 1) for passages of a 7-unit test train (locomotive, 5 passenger cars, locomotive) with regularly varied speeds of \(v_{T}\) = 63, 80, 100, 125,140 and 160 km/h. The measurement points are documented in Figures 2 and 3. The ground vibrations were measured at the soil surface from 3 to 50 m (tunnel line) and from 3 to 100 m (surface line) horizontal distance from the track with geophones (active velocity transducers Geospace HS-1 with 4.5 Hz natural frequency). Geophones were also used to measure the vibrations of the different tracks at two rail and six sleeper positions. The response of the bridge to the train passages was measured at 5 bridge deck positions. The vehicle vibrations were measured by Deutsche Bahn with 15 accelerometers, and the data were re-registered and evaluated by the author ([PERSON]). In addition, on the same tunnel and surface lines, a measurement campaign of BAM [32] and German Railways [33] with the high-speed train Intercity Experimental (locomotive, 2 passenger cars, locomotive) was performed in 1987, which will be evaluated here for the tunnel-to-surface reduction to cover the whole range of train speeds from 63 to 280 km/h. The vibration measurements were sampled at 2 kHz by a DIFA-SCADAS II measurement system with a 72 sample-and-hold 16-bit amplifier and filter channels (automatically adjusted to one third of the sample frequency). The software DIFA D-TAC was used during the measurements and the raw measurement data were analysed by home-written procedures. Some measured time histories are presented in Figure 4 to demonstrate the quality of the signals and the typical behaviour of the different measurement points. Figure 1: Measurement sections at (**a,b**) the bridge, (**c,d**) surface and (**e,f**) tunnel lines, cross sections (**a,c,e**) and view from the test train (**b,d,f**). Figure 2: Measurement points on the bridge and surface sections. Figure 3: Measurement points on the tunnel section. The time histories of the vehicle vibrations in the tunnel (Figure 4a) show the behaviour on the slab track up to \(t=1.0\) s and then the transition to the ballast track. The vehicle on the bridge (Figure 4b-d) shows greater vibrations during the entering and leaving of the bridge at \(t=0.0\) and \(1.0\) s. The car body vibrations show the longest vibration periods and the lowest frequencies, which can be seen in Figure 4d for the bridge, whereas the vibrations of the bogies are somewhat faster. The wheelset (axle-box) accelerations have the most regular behaviour with a dominant quasi-stationary high-frequency component (Figure 4b). The vibrations of the track (Figure 4e) clearly show the passage of each wheelset which can also be found in the near-field ground vibration (Figure 4f). The character of the ground vibrations changes strongly with the increasing distance from the track. At 10 m, there are rather stationary and wide-band ground vibrations (Figure 4g), whereas the ground vibrations in the far field (Figure 4h) are almost mono-frequent. These differences are shown for the surface track whereas the tunnel induced ground vibrations at the surface do not change significantly. In addition, the maximum amplitudes (on the bridge, tunnel and surface lines) in Figure 5 show  
Figure 4: Measured accelerations of the vehicle (**a**–**d**) and velocities of the track and soil (**e**–**h**); (**a**) bogie in the tunnel, (**b**) wheel/axle-box, (**c**) bogie and (**d**) car body on the bridge; (**e**) sleeper and soil at (**f**) 2.5 m, (**g**) 10 m and (**h**) 100 m distance from the surface track.