Squashed on a commuter train in sweltering temperatures, the thought of sitting on a block of ice may hold a certain appeal.
Now, such a daydream could become reality, as transport bosses consider stashing giant ice cubes underneath seats to cool carriages.
Air, chilled by passing it over the ice, would be pumped into the carriages when the trains are underground to keep temperatures down.
The technology - one of several schemes Transport for London is ploughing a total of £150 million into in an attempt to tackle heat on the Tube - is undergoing laboratory tests at the moment and could be tried out on a train as soon as next year.
If successful, blocks of ice - or a similar manmade material - could be installed on all trains running along on the 45-mile Piccadilly Line which runs from Middlesex via central London and into the North London suburbs.
Key to the scheme is the ability of ice to absorb large amounts of heat as it melts and changes to water.
Under the plans, blocks of ice would be hidden from view in refrigerated tanks stored underneath seats.
Above ground, where temperatures are generally lower, the ice will simply be kept in its frozen state.
But, when the train goes underground, the refrigeration will be switched off, allowing the ice to slowly melt.
As this happens, air will be cooled by pumping it over the ice, which absorbs much of the heat.
The cool air is then pumped into the carriage - likely through the vents found behind the seats on many trains.
When the train goes above ground, the meltwater, contained in a tank, is refrozen, ready for the cycle to start again the next time the train goes underground.
It is likely each carriage will have multiple ice blocks, with one block and set of refrigeration equipment supplying up to six seats.
The size of the blocks is still to be decided but they will have to be small enough to fit under the seats.
If trials prove successful, the technology could be introduced on all Piccadilly Line trains.
As yet, it is unclear whether existing trains would be adapted or whether it would be introduced after 2014, when all trains on the line are due to be replaced.
Other schemes being considered to cut temperatures, which reach an average of 31C below ground in the summer, include cooling tunnels by running pipes filled with cold water through them.
Although this plan sounds "cool", I am still skeptical of the plan due to the massive amount of ice blocks required to produce the desired temperature!
Tags: Ice Blocks | Tube