For those who won't bother to RTFA: the trains run cooler than other trains, so they are taking advantage of the difference such that the net result is the same temperature in tunnels, but the interior of trains can be cooler.
It's more like budgeting at a home level, in that you have a set limit of heat that you can spend, and choosing to spend it less on equipment like brakes, traction motors, etc. and more on air conditioning means still remaining in budget.
Their overall limit of heat output by the trains remains the same. The tunnels won't be any hotter than they are now, thanks to savings found in other systems.
onetimeuse92304|2 years ago
Here we improve the trains to emit less heat and immediately spend it on air conditioning.
In the meantime the debt (tunnel excess heat) continues to rise and somebody else in the future will have to pay for it.
NamTaf|2 years ago
Their overall limit of heat output by the trains remains the same. The tunnels won't be any hotter than they are now, thanks to savings found in other systems.