"Hundreds stuck in Tube derailment", BBC reports
This story will strike a chord with any who were similarly stuck for 2 hours in north London back in May. Rising temperatures and humidity inside the carriages, as ever, were a problem.
Richard Porter, of the London Ambulance Service, said temperatures in the tunnel could have been around 26C (79F) to 31C (88F).
"People were uncomfortable and sweaty", he said. "The rescue operation was very swift."
"We had water and were helping people very quickly."
Swift action by the emergency services and LU staff will, undoubtedly, have played an important part in preventing heat casualties.
The problem goes something like this. First of all the train comes to a halt. Natural ventilation through the train carriage ceases and heat from the passengers and moisture soon starts to make the carriage warmer and more humid. In time passengers struggle to cope with the rise in thermal stress.
Key to managing these situations is the time it takes to decide whether the train can proceed soon, or whether an evacuation is more practical.
It takes time to evacuate a busy underground train. The passengers have to de-train (as it's known) through the driver's compartment. One by one. Able bodied along with the elderly. In a busy train this takes time, sometimes an hour or so. Before they can do this power to the track has to be switched off. During this time the conditions in the train deteriorate. Passengers can start to succumb to heat strain. What is less well known is that the casualty rate rises dramatically once body temperature rises above 39 deg C. So, it takes time for general feelings of discomfort to translate into the small numbers of passengers fainting. BUT it doesn't take much longer for larger numbers of passengers to have serious reactions to the heat, some of which can be near fatal.
An incident back in 2000 illustrates this well, when 2000 commuters were stuck for some 2 hours in sweltering conditions. The numbers of casualties was distinctly higher AND of a more severe nature.
Fortunately, today, the weather was mild.
Speaking personally, I avoid the tube whenever I visit London. Well, its true I could lose a couple of pounds - so the walk does me good. However, if I did have to use it regularly, I'd take a litre bottle of water with me and some kind of portable battery operated fan system.