Testing during normal subway operation
The suspension seat prototype was validated in the subway
during normal operation with 6 different operators having
weight around the 5th, 50th and 95th percentile of the
operator population weight. The measurements have been
performed on the Montreal subway yellow line, between the
Longueuil-Université-de-Sherbrooke and Berri-Uqam stations,
where whole-body vibration levels were shown to be higher1).
Vibrations on the floor were measured near the operator with
a triaxial accelerometer (PCB 356B41, without the seat pad),
while the vibrations on the seat cushion were measured with
an accelerometer seat pad (B&K 4322 with three charge
amplifiers B&K 2635). At both locations, the vibrations in the
three axes were measured according to the basicentric axes2),
as shown in Fig. 5. The time data were recorded and analyzed
using a B&K Pulse acquisition system. For each operator,
the measurements were performed over two round trips of
about 20 min each. The operators were asked to adjust the
suspension height to their preferences at the beginning of the
measurement. However, it was requested to keep a minimum
of 3 cm from the limit stops to avoid end-stop impacts.