The East Asian economic miracles are all heavily export dependent. Part of the pillar of this industrial strategy is to heavily support emerging technologies, because they can then gain economies of scale, first mover knowledge, etc. This has happened before, with technologies like plasma screens, LCDs and LEDs, and is now happening in China with solar panels and electric cars. They have developed such advanced manufacturing capabilities so quickly and are now almost insurmountable market leaders, or at least major competitors.

Railways are also part of this strategy. China, Japan and Korea all export railway products from high speed rail to subways to monorails, and so in this context rubber tired metros are another niche technology to get an edge in. Note that this strategy doesn't always work; no one outside of these countries is very interested in maglev trains, for example.

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The other part of this is development finance. Countries that do not have know-how with big infrastructure projects often look to international institutions to build projects and secure financing. And part of the deal is that if you take French money you must spend it on French suppliers, and this is true for basically any country doing this kind of lending, so basically the lender is getting both interest payments and spending towards its economy. The Chinese and Japanese compete a lot for railway projects in particular; Japan built the Taiwanese HSR and the Hanoi and Ho Chi Minh City metros, China is currently building high speed rail in Thailand and Laos, etc.