Although you can’t tell from the photo the Brompton rider is on one of Sheffield’s better pieces of cycling infrastructure - a raised path of reasonable width (about 2m) which runs parallel with the ring road outside the train station. Probably just as well, as the driver about to pass doesn’t look very with it.
A Portland father has constructed the ITandem bicycle because his son is not big enough to ride a bike on his own. Transforming a brompton bicycle to create a tandem bicycle which allows an adult and child to ride together.
Thanks to Annette for the link
You can see another interesting take on a tandem here