There'a railway car with passenger seats looking roughly like this (please ignore the seatbelt):
Seats are arranged in ICE fashion - two rows with a passage between them, two seats in each row, each passenger is facing the back of the next row (so he has all the footspace for himself but can only stare at the window, the neighbors and the back of the set in front of him all the way - that's very humane, but causes a problem which I'm about to explain).
Below each seat is a metal box with a power outlet - I schematically drew the box and the orange dot is where the outlet is accessible from. It is slightly recessed so that passengers don't accidentally bump into it.
I find this location quite reasonable - the outlets is easily reachable and doesn't interfere with anything, passengers cannot accidentally kick it, cannot accidentally wet it with rainwater from their clothes, spilling drinks onto such outlet is not easy.
The problem is passengers cannot find the outlet in there. When they enter the car they are not thinking about outlets yet - they need to find their seats, cram their belongings onto the shelves, say hello to their neighbors, call home and say they are departing, etc. Then they take their seat and it's quite clear that a person seating on such seat does not see the outlet - the outlet does not advertise itself in any way.
So passenger either ask conductor for assistance or just plain spend all their way not knowing there're outlets. The best chance for them to find there's an outlet is seeing their neighbors using such outlets.
How could outlets introduce themselves?
A rather direct way would be to place a sticker such that it's in front of each passenger's face saying "Hey, we have outlets right below the seat, enjoy" but it doesn't sound elegant - those stickers will forever be there and visually clutter the environment.
Could there be some other way to help passengers find those outlets?