DELIVERABLE 2.8 - urban track

3.4. MEASUREMENTS
D0208_STIB_M24.doc
TIP5-CT-2006-031312 Page 36 of 44
URBAN TRACK Issued: August 13, 2008
Quality checked and approved by project co-ordinator André Van Leuven
The verification of the advantages of modern track alignment design compared to conventional one is
done by measurement of accelerations at the metro train of Wiener Linien. The main task is to find the
influence of track alignment design by measurement of the accelerations at the vehicle. The
measurements were done with extremely sensitive, low frequency, accelerometers (applied sub critical,
displacement s = F/c = - a/�0², �0 = 2(((f0 characteristic frequency). The first test-measurement with 8
channels was realized one morning and followed by the main-measurement of the track geometry with
up to 18 channels in 3 nights during pause of normal operation. The measurement of the whole metro
net with 20 channels each line was realized twice in two days during normal operation with high
frequency sensors in up-direction at the axle bearings.
Accelerometers were mounted on the axle bearings in transverse (low frequency) and vertical (middle
frequency for ripple) direction, in the middle of the bogies, at the bottom of the vehicle’s body in
longitudinal, transverse (triaxial) and vertical direction over both bogies and in the middle, at the left and
right outer walls in vertical direction and beneath the roof in transverse direction approximately over
both bogies.
Marker equipment with inductive approach switch for the exact spatial determination of the vehicle’s
position was used. Therefore, mean values could be taken for different runs at the same position. A
series of measurement runs were performed at the night both in travelling and in reverse direction and at
different speeds.
The procedure for three test-curves at the metro U4 was the following:
Production of the ideal old conventional geometry with clothoid and constant cant gradient.
Measurement of accelerations with measurement train.
Re-tamping to Viennese transition curve and cant gradient.
Measurement of accelerations with measurement train.
Evaluation of the actual accelerations relative to the nominal accelerations (maximal 0,654 m/s²).
Calculations of the dispersions = SQRT(variances) of the mean accelerations within the vehicle’s body
in [m/s²].