On the busiest Hanshin Expressway network in Asia, Kansai Expressway Co., Ltd. in Japan has recently introduced the Kobelco XG25U tunnel-specific mini excavator for nighttime tunnel maintenance operations. Facing a daily traffic volume of 200,000 vehicles and strict road work regulations (with a nighttime work window of only 3 hours), traditional maintenance equipment could not meet the stringent requirements for rapid deployment and efficient operation.
“We tested seven models from both domestic and international manufacturers, and ultimately chose Kobelco because of its ‘quick change system’,” said Kenichi Nakamura, head of the maintenance department, pointing to the equipment working inside the tunnel. “It takes only 90 seconds to switch from transport mode to operating mode, and its unique low-profile mode allows the equipment to travel at full speed in the emergency lane with a 3.5-meter height limit. Most importantly, its exhaust gas treatment system fully meets the air quality requirements for enclosed spaces.”
This equipment, deeply customized for Japanese road regulations, integrates several innovations: a foldable cab that can be lowered to 2.1 meters during transport, a three-stage exhaust gas filtration system that keeps PM2.5 concentrations in the tunnel within safe limits, and millimeter-wave radar that can automatically identify the location of tunnel wall defects. In the recent major overhaul of the Osaka Loop Line tunnel, this equipment reduced the single-operation time from 4 hours to 2.5 hours, reduced the number of workers by 60%, and achieved the breakthrough of not completely closing the tunnel during construction.
The Japanese Ministry of Land, Infrastructure, Transport and Tourism has included this equipment in its “Recommended List of Next-Generation Road Maintenance Machinery,” and expressway groups in Tokyo, Nagoya, and other cities have already started procurement procedures. Kobelco Japan is currently collaborating with Osaka University to develop an intelligent tunnel inspection robot system based on this platform, which is expected to be put into practical use in 2026.
