These days, they are older, and perfectly capable of surviving the trip without trouble, but when they were smaller, things were more difficult: with no space for a pushchair, and frequently no space to sit, we had to carry them. This created more problems, because we then had no hands free to strap-hang ourselves.
This is a simple Make that frees up your hands, and gives your children a bit of safe independence.
Step 1: Materials
(*I asked Conker-X)