Page 17 - 360.revista de Alta Velocidad - Nº 5

Lightweight primary structures for High-speed railway carbodies

Table 1. Main technical features
Maximum speed 365 km/h

Operating speed 330 km/h
Passenger capacity ca. 500 - 600
Typically two powerhead and 12 coaches but adaptable to client
Trainset configuration
specifications
Track gauge (mm) 1435-1668
Floor height (mm) 760 above TOR
Length (m) 201.9
Width (mm) 3200
Tare weight (tonnes) 317
Number of axles 21
Passengers/WC 40-55

Power supply 25kV AC (tri-voltage optional)
Power 2 x 4400 kW (tri-voltage optional)
Brakes Powerhead: regenerative, rheostatic and air brakes Coaches: air brakes
Standard UIC/ETI

3. Challenges of new lighter structures

All the above requirements imposed to the new trains usually imply the reduction of the weight
of the primary structure in order to accommodate new payloads, be more efficient, etc.
The design of the lighter structures that can withstand more than the previous one, usually
supposes challenges when the structure is analysed in term of stiffness (natural frequencies,
damping ratios and mode shapes) and noise isolation. Lighter primary structures under more
restrictive loads (without changing concept design) are prone to have low natural frequencies
that imply poorer ride comfort values for passengers, (Dumitriu, 2017; Chatti, 2006).
In general, the running gear interacts with the track producing vibrations with different amplitudes
and frequencies depending on the line, tracks, defects or maintenance program. The more speed,
the more amplitudes and higher frequencies levels (see Figure 7). To avoid passenger discomfort,
the carbody should be designed with sufficient stiffness in the vertical, lateral and torsional
directions to avoid coupling of frequencies between the running gear and carbody, both should
not display similar Eigen frequencies. In addition the interfaces between bogie and carbody should
be carefully analysed in order to avoid undesired bypasses of forces through them.

Figure 7. PSD of acceleration at unsprung mass level depending on speed for HS track Madrid-Barcelona.

International Congress on High-speed Rail: Technologies and Long Term Impacts - Ciudad Real (Spain) - 25th anniversary Madrid-Sevilla corridor 15