100mph trains to Aylesbury

[whole diary]

[ChrisB]

Again, disagree - charging only while not using all the power generated, so no increase while diesel running/burning.

And 25% is 25% (a quarter reduction) is a large amount, sorry. Yes, 100% saving (less whatever it takes to generate that leccy) is huge - but you can't seriously deny 25% is still a large reduction (unless the 100% is considered negligible, in which case why are we bothering?)

[broadgage]

I can not agree.

How is a diesel engine to produce extra power (whether to charge a battery or for any other purpose) without also burning more fuel and producing greater emissions of carbon dioxide ?

It is basic physics, that to produce more output power will require more fuel.

[RichT54]

I wonder what percentage of the battery charging comes from the diesel engine and what percentage comes from regenerative braking?

[Ralph Ayres]

The reference to Aylesbury is a bit misleading as I'm pretty sure no stretch of the Aylesbury-Marylebone direct line allows 100mph running. The train will presumably be based at Chiltern's Aylesbury depot but as the article says, it is also going to be used on the Marylebone-High Wycombe-Oxford line where it will indeed be able to reach 100 mph.  I'm staying out of the hybrid good/bad discussion; it's far from clearcut, although at the very least I suppose it does allow aspects of battery technology to be explored which might be of clear benefit in future.

[Celestial]

There will indeed be no emissions in battery mode, but in diesel mode there will be EXTRA emissions in order to produce the energy used to charge the battery.

A reduction of 25% in fuel consumption and therefore also a reduction of 25% in carbon dioxide emissions is a relatively small reduction if compared to the use of an electric train. (battery powered or OHLE powered)

Surely it depends on how much of the battery charging is from regeneration on braking - likely to be a greater proportion on suburban services with many stops? So not all of that battery power has resulted in extra emissions.

And the comparison with electric needs to recognise that there is still a carbon footprint with electric, so a 25% saving is a greater proportion of potential saving you would get if the service was electrified. (eg, if a fully electric service resulted in a reduction in carbon emissions of 80%, then the proportionate saving of the hybrid approach is 25/80 =31%).

If you can get that sort of saving in a couple of years from modifying existing rolling stock that sounds like a no-brainer given the costs and timescales involved in a large scale electrification programme (assuming the trains have a long enough expected life to make it financially viable).

There's also the improvement in local air quality and noise to consider too, apparently a big issue at Marylebone. At the places where it is likely to be an issue, you get more or less the full benefit of electrification with this solution. 

[paul7575]

If you can get that sort of saving in a couple of years from modifying existing rolling stock that sounds like a no-brainer given the costs and timescales involved in a large scale electrification programme (assuming the trains have a long enough expected life to make it financially viable).

A GWR^▸ (Great Western Railway) insider posting in the WNXX^▸ (Stored Unserviceable, Mainline Locos HQ All Classes) forum reckons it’s almost certainly not happening to any of the GWR fleet.  Every year the DfT^» (Department for Transport - about) and treasury delay it just reduces the BCR^▸ (Benefit Cost Ratio) further.

I don’t think many people are expecting Chiltern to go for more conversions, their current “national rail contract” with DfT apparently only allows for two demonstrators.

Paul

[Celestial]

There is however a reasonable amount of more modern dmu stock where the BCR^▸ (Benefit Cost Ratio) is likely to be more attractive. Though given I gather operating companies need treasury approval for every paper clip ordered these days, I suspect the environmental benefit will be given minimal weighting in any assessment unfortunately, despite all the claims to the contrary about trying to promote a green railway.

[grahame]

... Though given I gather operating companies need treasury approval for every paper clip ordered these days...

Not quite. I believe that there's a cap of £1,000 [on train repairs] without sign-off from the DfT^» (Department for Transport - about), and that could include quite a few paper clips if it's to pin together the paperwork thus generated  ... confirmation of that, or "just a rumour without substance" would be interesting!

[paul7575]

It’s now being suggested in Rail UK^▸ (United Kingdom) forums that the second demonstrator has been cancelled, (although no official quote).  For me that lengthens the odds we won’t be see it in any GWR^▸ (Great Western Railway) trains.