One of the few remaining questions regarding millimeter wave-based 5G networks is whether they’ll be able to deliver cellular service to fast-moving vehicles — such as cars, subway trains, and conventional trains. The answer is “yes,” suggests top Japanese carrier NTT Docomo, which today announced successful completion of an impressive stress test: a multi-base station handoff of 5G signals to a device on a next-generation Shinkansen bullet train.

Docomo’s test was noteworthy, thanks to the speeds of both the train and the 5G service. While the Shinkansen traveled at 283 km/h (~176 mph), the 5G signal delivered data speeds over 1Gbps, successfully transmitting 8K video from the network to the mobile device and streaming 4K video live from the mobile device to the network.

While engineers have been confident that various 5G technologies would make such a feat possible, actually making them work together is an achievement. Vendors are continuing to improve theĀ practical distance and handoff techniques for millimeter wave hardware.

Calling its bullet train test a “world’s first,” Docomo used three 28GHz millimeter wave base stations with advanced beamforming and beam-tracking features capable of conveying and handing off ultra high-speed data signals while the train was in motion. If the test worked on one of the world’s fastest trains, that’s a good sign for millimeter wave 5G handoffs to cars and slower trains.

Japan uses bullet trains to facilitate transportation between major cities, such as Tokyo, Osaka, and Kyoto, and will be commercially deploying the new N700S-model Shinkansen in 2020, just before next year’s Summer Olympics in Tokyo, which is also expected to be a showcase for 5G cellular and 8K video technologies. The test took place between Mishima and Shin-Fuji stations, near where the country’s famous mountain Mt. Fuji can be spotted.

Despite a government ban on Chinese-made 5G network hardware, NTT Docomo kicked off early 5G services on September 20 and plans to offer 5G across all 47 Japanese state-sized prefectures by the end of June 2020. Rival SoftBank recently decided to accelerate its own 5G deployment plans in Japan by two years.