Optimizing train carriage utilization - signs on platforms

For various reasons different carriages in trains get fuller than others. This reduces the comfort of passengers, and in extreme cases means that other passengers do not have enough space to board.

But this is a fairly simple problem to solve with existing technology. We can measure the occupancy of a carriage in numerous ways:

• optical cameras coupled with image recognition technology
• thermal imaging that captures the number of separate heat sources, or perhaps the aggregate heat being emitted
• thermometers would probably be sufficient to assess the occupancy to some degree
• pressure sensors on the seats or floor
• carbon dioxide levels
• optical beams measuring entry and egress
• etc

And we can communicate that information to passengers at subsequent stations. For example, the platform could have lights built into the floor which are greener where the carriages are emptier, and redder where they are fuller.