London has made some moves against buses etc sitting idling at bus termini with engines running all the time. I don't think comments to the adjacent residents of "well you live on a road so must expect vehicles" got very far. This is likely to extend very soon with a campaign against diesel road vehicle pollution, which has become a significant problem, especially as private cars have to an extent been squeezed out from central London by various measures and most road vehicles now, buses, trucks, taxis, millions of Uber chancers, etc, are invariably diesel. Railway diesels will get swept up in this.
I think saying the diesel must thrum away for 17 minutes before departure will be laughed at by all the politicians and activists - and by a significant number of engineering professionals as well. I bet there were those in the 1950s who said that inner London steam loco sheds needed to light up 50 steam locos on Sunday afternoon 12 hours before being needed, and got the same short shrift from the Smokeless Zone legislators as well.
Did you realise that trains are responsible for 8% of the NOx emissions in London? That is the same percentage as all the TFL buses and 4 times more than taxis.
One would hope that this would receive as much attention, but is currently being ignored.