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In
the beginning, wooden materials were used for the body of
the rolling stock. Then normal steel materials were adopted
afterwards to improve safety against fire or collision.
However, as normal steel materials corrode after continued
usage over a long period of time, thicker plates with room
for corrosion must be used, and they must be repaired after
a certain extent of corrosion.
On the other hand, it is against the current trend to increase
the thickness of the plates for the room of corrosion, as
it is required for rolling stock to be lightweight to increase
its transportation capacity and profitability. Therefore
the aluminum-alloy train was developed to realize production
of the rolling stock with corrosion-free materials. Aluminum
alloy is used as a main material for the airplanes, as it
has one-third specific gravity and equal strength of steel.
It is considered ideal for the materials of rolling stock
as well, however it took a long time to become popular in
reality. It was used only for the outer panels of rolling
stock, small cable cars, and ropeway gondolas. The reason
was that it was expensive, and that it requires advanced
technology to be processed. Some experimental railcars using
aluminum alloy materials were produced before World War
II, and we also produced Type "MOHA63" trains using surplus
duralumin materials for airplanes during the post-war period
when materials were in short supply.
The first mass-produced aluminum-alloy train for practical
use was introduced on the London subway in 1952. Many aluminum-alloy
trains came into service in Switzerland and in Germany,
where the R&D of aluminum-alloy trains were very active.
The greatest benefit of an aluminum alloy train is that
its body structure weighs half of that made of steel. It
reduces the weight of a whole train by 10 to 15%, which
can save the cost of power more than the additional cost
of aluminum alloy materials.
We had been paying attention to these benefits of aluminum-alloy
trains since long ago, and we entered into a technical partnership
with WMD, a German company. We sent our engineers to learn
designing and manufacturing skills, and in 1962, we developed
our country's first ever aluminum alloy railcars, Type 2000
electric trains No. 2012, 2013, and 2505 for Sanyo Electric
Railway.
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Development
of the aluminum-alloy train
