Is it realistic to use 802.11r in a subway tunnel?

Question

Computer networks

At the moment I am writing a graduation project on the topic: "The project of a radio access network for the Dzerzhinskaya line of the Novosibirsk metro." I chose this non-standard topic because I was inspired by an already existing project in the Moscow Metro.
After reading some reviews of the technical component of the project in livejournal, I wanted to improve the radio channel for my project to Gigabit (that is, from the wifi server rack to the equipment installed in the train cars). The question arose: is it possible to make this gigabit channel via Wi-Fi 802.11 AC, where seamless roaming will be used to switch between routers in cars. I can not find in the IEEE specifications what is the minimum speed of the subscriber (tobish train car) is acceptable for this very roaming (Fast BSS / 802.11r). Rather, it will be easier to use a 3G, 4G modem, because in Novosibirsk there is not such a deep metro as in Moscow ...
wi-life.ru/texnologii/wi-fi/mobilnost-v-setyax-sta... - 802.11r

Answer 1

You're a little behind:
802.11ad is a new standard with an additional 60 GHz band (licensing-free frequency). The data transfer rate is up to 7 Gbps.
802.11as is (presumably) a new standard using resonator slot antennas operating at 135 GHz. Data transfer speeds up to 20 Gbps. The antenna gain is 5.68 dB.
Read about the standards of the future, implementation will be easier with them.