Underground economy

Design students contribute ideas for boosting non-fare income and improving the travel experience of Kunming's subway, Lin Qi reports.

When Line 1 of the Beijing subway, the country's first subterranean railway, was officially opened in 1969, it served only 10 stations and carried few people.

Today, the greatly extended route has become one of the busiest along the capital's rail network, and such day-to-day mass transit has also been established in other populous cities across China, where subway construction is booming.