To accommodate the summer's average daily flow of 30,000 passengers, Line 8 has added extra services, with trains now running every 4 minutes, a 25 percent increase in capacity.

For a more historical perspective, the No 5 bus offers panoramic views. Starting at Caihuying Flyover, it passes significant landmarks like Qianmen and Tian'anmen, closely paralleling the axis.

The journey is enhanced by a looping audio guide, and the line has recently introduced a QR code that passengers can scan to get in-depth cultural insights on their mobile devices.

A tourist, Liu Gong, from Hebei province, praised the comfortable and scenic journey.

"The No 5 bus passes numerous famous Beijing attractions, and offers stunning views," he says. "The bus is cool, and the environment is clean and well-maintained."

Zhang Lu, a No 5 driver, hopes the bus becomes a cultural showcase for the Beijing Central Axis.

"We invite everyone to experience No 5 bus. Our commitment is to provide a safe, eco-friendly, and comfortable service, making No 5 a cultural gateway for both local and international visitors," Zhang says.

Wong Kai-wing contributed to this story.