China plans to spend 3.5 trillion yuan ($503 billion) to expand its railway system by 2020 as it turns to investments in infrastructure to bolster growth and improve connectivity across the country.

The high-speed rail network will span more than 30,000 kilometres under the proposal, according to details released at a State Council Information Office briefing in Beijing Thursday. The distance, about 6.5 times the length of a road trip between New York and Los Angeles, will cover 80 per cent of…