Issue: Obesity and sedentary lifestyles are the worlds number one killer. Possibly a billion people or more travel for work everyday. As urbanisation continues and cities expand, this number is only set to increase globally. More and more time is being spent travelling making physical activity even harder to fit into everyday.
Solution: Enter the moving train. Commuters today generally spend their time on their screens or listening to music. However this train will have carriages filled with steppers and other machines which do not take up much space but are most effective. Remove the seats and replace it with pull up bars etc.
Cost: To keep cost down, these could either be special carriages or special trains which only run at peak times in the mornings and evenings especially for workers.
Environment: The power of the rowing and any other energy from any of the machines could be preserved and used to power some aspect of the train. Environmentally friendly and helps solve the unfit nation. It might also encourage more people to use public transport, which would be a positive step in being more environmentally friendly.
Branding: One needs to TRAIN IT in all sense.
Personal: I use the train for more than 3 hours a day and so know how hard it is to fit exercise into my day. It is why I strongly believe we need seamless ways for physical activity to be incorporated in our lives whether this is on the commute itself or even at compulsory fitness sessions during work hours.
2 months later, on April fools day, Virgin Trains came up with pretty much the same thing which has been demonstrated here.