Suggestion for improving London tube trains:
A three-foot sheet of glass suspended from the roof of the train, running exactly down its centre.
This glass sheet would enable passengers to make better use of the fact that maps of the tube line are mirrored on each side to follow the direction of travel. Passengers seated on one side of the tube would be able to see precisely to which station stop a passenger seated on the opposite side of the tube is pointing whilst engaged in animated conversation with his/her friend/lover in an unidentified language.
Please note that this facility could also be used by a passenger for surreptitiously watching passengers seated next to them. Whilst such behaviour is legal, it is probably undesirable, and would discouraged by large decals on the glass such as:
Do not ogle in the glass