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Drones are flying beneath the ground in Japan, and here’s why

You may think of a drone as a machine that ordinarily flies high in the sky, but in Japan, they’re being flown beneath the ground, too.

Tokyo Metro, which operates much of the capital city’s sprawling subway network, is using the technology to inspect the upper sections of train tunnels, Japan News reported this week.

Instead of using scaffolding and elevating platforms that take time to set up, the drones can easily fly right up to vents or other parts of the tunnel, sending a live video feed to the nearby operator. High-resolution still images are also captured for later analysis.

Tokyo Metro's inspection drone.

The remotely controlled custom-built copter is enclosed in a spherical 22-cm-diameter plastic cage to protect it from occasional knocks as it flies around inspecting the tunnels. Weighing 2.5 pounds (about 1.15 kg), the machine is only a shade heavier than DJI’s Mavic 2 Pro quadcopter.

A demonstration of the system (below) shows the operator skillfully flying the drone, with the machine’s small size enabling it to slip between pillars and through gaps in the concrete as it searches for issues such as structural irregularities or water leaks.

東京メトロ トンネル検査をドローンで 今後は高架橋も

Although a visual inspection from the ground is sometimes enough to determine whether there’s a problem that needs to be addressed, often it’s difficult to tell for sure, in which case scaffolding needs to be constructed, or a works vehicle with an elevating platform deployed, for a closer look.

The drone is much quicker to set up and more cost-effective than these traditional methods and is able to gather more detailed data in a short period of time.

As Japan News notes, Tokyo Metro’s nine subway lines cover 121 miles (about 195 km), with 85% of the track running through tunnels. The drones are currently being used only on one of the city’s subway lines, but the plan is to deploy them on all 10 of its lines before the end of this year.

The deployment of drones beneath the ground is one of the more unusual uses we’ve come across, but it makes total sense. And it’s just the latest in a growing number of examples of how the technology is transforming the way we do our work.

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