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Would it be possible to shut off the engine when entering the peripheral of London and coast into the station with zero emissions? Perhaps use an electric locom

Would it be possible to shut off the engine when entering the peripheral of London and coast into the station with zero emissions? Perhaps use an electric locomotive to push or pull them out of London, again with zero (local) emissions.

lorenzhs 7y ago
Diesel trains built in the last two decades (e.g. class 220/221/222) are already Diesel-electric, meaning the Diesel engine drives a generator which powers an electric motor. Doing it this way is more effective because you can run the Diesel engine under optimal conditions all the time. This also makes it possible to build bi-modal trains that run on Diesel on non-electrified tracks and use a pantograph on electrified bits (like London). That's what is being done in the UK now under the Intercity Express programme in order to replace the old Diesel trains (HST/Class 125): https://www.hitachi-rail.com/products/rolling_stock/bi_mode/index.html https://www.hitachi-rail.com/products/rolling_stock/bi_mode/... - these are the class 800/801/802 trains mentioned by vertex-four in a sibling comment.
- makomk 7y ago
  The trouble with this is that the trains have to have both a full set of diesel generation equipment for non-electrified operation and a full set of power conversion equipment for electrified mode, plus some way of switching between the two. The class 800 doesn't seem to have done a terribly great job of this; there's been huge teething problems with their introduction and rumour has it that the underfloor diesel engines simply can't operate at outside temperatures above 30 C or so due to inadequate cooling in order to fit them into the space available.
  - youngtaff 7y ago
    The 800's west out of Paddington don't seem too bad I regularly get the Cheltenham to Paddington train, and apart from the slight extra delay at Swindon while they switch power haven't had any problems with them. Some of the early seat covers are being replaced because they don't wear well though
vertex-four 7y ago
Trains into London are being gradually replaced with electrics and hybrids - see the Class 800/801/802 ("IET", "Azuma"). These will use diesel nowhere near London. Dragging trains into/out of London with an electric loco would pretty much kill the frequency of the lines. This isn't the US where we might get five long-distance passenger trains a day - London King's Cross and Euston are busy, with service patterns at breaking point as it is. There's nowhere outside the city where trains could stop and wait for a locomotive, anyway.
einpoklum 7y ago
With purely diesel trains - No, it wouldn't. There's still quite a bit of friction, plus there are turns (= even more friction to apply the turning force). Only if it's a diesel/electric, but then you're not really turning off the engine.

lorenzhs 7y ago

Diesel trains built in the last two decades (e.g. class 220/221/222) are already Diesel-electric, meaning the Diesel engine drives a generator which powers an electric motor. Doing it this way is more effective because you can run the Diesel engine under optimal conditions all the time. This also makes it possible to build bi-modal trains that run on Diesel on non-electrified tracks and use a pantograph on electrified bits (like London). That's what is being done in the UK now under the Intercity Express programme in order to replace the old Diesel trains (HST/Class 125): https://www.hitachi-rail.com/products/rolling_stock/bi_mode/index.html https://www.hitachi-rail.com/products/rolling_stock/bi_mode/... - these are the class 800/801/802 trains mentioned by vertex-four in a sibling comment.

makomk 7y ago
The trouble with this is that the trains have to have both a full set of diesel generation equipment for non-electrified operation and a full set of power conversion equipment for electrified mode, plus some way of switching between the two. The class 800 doesn't seem to have done a terribly great job of this; there's been huge teething problems with their introduction and rumour has it that the underfloor diesel engines simply can't operate at outside temperatures above 30 C or so due to inadequate cooling in order to fit them into the space available.
- youngtaff 7y ago
  The 800's west out of Paddington don't seem too bad I regularly get the Cheltenham to Paddington train, and apart from the slight extra delay at Swindon while they switch power haven't had any problems with them. Some of the early seat covers are being replaced because they don't wear well though

vertex-four 7y ago

Trains into London are being gradually replaced with electrics and hybrids - see the Class 800/801/802 ("IET", "Azuma"). These will use diesel nowhere near London. Dragging trains into/out of London with an electric loco would pretty much kill the frequency of the lines. This isn't the US where we might get five long-distance passenger trains a day - London King's Cross and Euston are busy, with service patterns at breaking point as it is. There's nowhere outside the city where trains could stop and wait for a locomotive, anyway.

einpoklum 7y ago

With purely diesel trains - No, it wouldn't. There's still quite a bit of friction, plus there are turns (= even more friction to apply the turning force). Only if it's a diesel/electric, but then you're not really turning off the engine.