The ADATS is a short-range dual purpose missile system. It was the first weapon system to combine SAM and ATGM capabilities into a single missile battery. However the ADATS proved problematic and unsuccessful.
RYNO Motors' single-wheeled electric scooter is self-balancing, has a turning radius of zero when stopped, & only takes up about as much space as a folding bicycle -- so it's conceivable that commuters could bring one onto a train.
I could use this as an outdoor pack or emergency pack. Multi-Purpose 1 day pack ( FirstSpear is a brand created by former U. servicemen, they develop enhanced light-weight load carriage solutions for the US Special Forces )