Now I would like to describe the concept of one-half weight reduction.
Conventional commuter trains were structurally too strong and the price, rather high in view of the quality, had not changed. So we decided to reduce the ratio of electric motor cars to attached cars. The conventional train had 6 motor cars and 4 attached cars. In System 209 this formation was reversed to 4 motor cars and 6 attached cars, which reduced the weight of the entire train. The weights of the rail car body and devices were also reduced along with the size of devices.
Concrete developments included a stainless steel body built in cooperation with rail car manufacturers by a new two sheet method. The structure was thoroughly analyzed by a finite element method. As mentioned earlier in the life cycle topic, weight was reduced by the VVF inverter, three stage altemating inductive motor and bolster-free bogie. Weight reduction was sought by simplifying structure and ensuring safety, without compromising current strength standards.
