Came across an interesting video on YouTube,
http://www.youtube.com/watch?v=YHwLQcKPIrk
I must confess to not knowing much about a "compressor" or indeed what might cause it to fail like that.
Would be interested to find out some more information.
Thanks
valenta.
Did you have it confirmed as a compressor fault? It certainly sounded like an air system fault of sorts.
Trains uses air for all sorts of things, brakes most importantly, doors, toilets, horns, the list goes on. I'm not sure that they provide cooling, there's normally separate fans for electrical components. The smoke may have come from an electrical fault on the compressor.
The compressor basically takes air and fills reservoirs all around the train. It compresses this air and allows these reservoirs to become pressurised at something like 8-10bar in some cases. This volume of air is enough to use multiple air systems around the train all at once if needed.
The compressor therefor is a vital bit of kit. Metros will certainly have at least two compressors so when one failed the second would have taken over but might not last too long as it may not be able to keep up with demand. It would however get the metro back to the depot.
The driver would have noticed a drop in air pressure and may have even had a fire detection or other alarm (even an emergency brake handle pulled by passengers) but often the best thing is for the driver to stop the train in a platform where access and egress is safer for all.
Hope this helps any questions feel free to ask