Japan now has railway apps which has live data including the crowding of each carriage and inside train temperature.
I hope Japan is not still on its saving energy drive as it was when we were there in summer. Thermostats on public transport and in many buildings had been raised and many places were uncomfortably warm. I remember being really quite hot on a train. Every so often the air con would come on and a wave of lovely cool air would wash over us but after it minute, the system would go off. Once home, I emailed a letter to a Tokyo English language newspaper with my opinion of their energy saving practices but then forgot to check if the letter from the whingeing gaijin was ever published.