How can public transport cut energy use

[Bald Rick]

The 5MW is rarely used except for short bursts of acceleration, and a braking profile can recover much of those bursts.

the computer used every watt of it leaving St P!

== Doublepost prevention - post automatically merged: 2 Apr 2022 ==

Well it's meaningless taking the question out of the wider policy context. You must know that.

we‘ll disagree on that, as the question didn’t have a ”wider policy context”.

 

[Irascible]

running fewer trains is clearly one possible answer to that, albeit not one that is necessarily desirable. (Although it might be on some lightly used services, such as my 5MW train home last night that had about 30 people on it.)

So is "only run trains downhill!", as is "move passenger transport to sail barge" ( coastal passenger wind-powered ships would certainly be a slightly less deliberately silly alternative to some routes - quite obviously still silly, yes ) and we haven't nailed down what public transport's energy footprint actually is either - does it cover manufacture of vehicles, or whether people's energy use in situ is more or less efficient than where they would otherwise spend their day, or is it literally just moving vehicles under the operation of a public transport body ( so delivery wouldn't count, nor would dragging the vehicles back up the hill by road ).

But yes, in a literal sense, removing public transport entirely would zero it's energy use. Let's stick to a holistic view shall we rephrase it as "How can public transport reduce it's energy footprint while maximising it's utility".

 

[AndrewE]

running fewer trains is clearly one possible answer to that, albeit not one that is necessarily desirable. (Although it might be on some lightly used services, such as my 5MW train home last night that had about 30 people on it.)

A few decades ago the Swiss considered shortening trains outside the peaks. They concluded that the shunting would take as much as they saved from main-line running as the trains were mostly loco-hauled. Maybe other costs came into that too.
However nowadays I wonder if it would be worth re-examining. Your 5MW train would presumably use about 3 MW if it was half the length, so if we plannned our services around double sets (properly connected throughout) but singles in the evenings it would save some energy, albeit at the cost of doubling the number of driving cabs to be built and carried round.
A benefit on the WCML would be that at times of day when the full train length was not justified a "fast" Scottish departure from Euston could couple with the previous hour's class 9 at Stafford or Crewe and then split at Carlisle or Carstairs, giving better connectivity and a much better service than now - or even pre-Covid - when passengers on the Class 9s are at the mercy of the connection into the shorter TPE services N of Preston for Glasgow and Edinburgh alternate hours.
Of course there is no Birmingham to Glasgow service at all at the moment...

 

[AM9]

A few decades ago the Swiss considered shortening trains outside the peaks. They concluded that the shunting would take as much as they saved from main-line running as the trains were mostly loco-hauled. Maybe other costs came into that too.
However nowadays I wonder if it would be worth re-examining. Your 5MW train would presumably use about 3 MW if it was half the length, so if we plannned our services around double sets (properly connected throughout) but singles in the evenings it would save some energy, albeit at the cost of doubling the number of driving cabs to be built and carried round.
A benefit on the WCML would be that at times of day when the full train length was not justified a "fast" Scottish departure from Euston could couple with the previous hour's class 9 at Stafford or Crewe and then split at Carlisle or Carstairs, giving better connectivity and a much better service than now - or even pre-Covid - when passengers on the Class 9s are at the mercy of the connection into the shorter TPE services N of Preston for Glasgow and Edinburgh alternate hours.
Of course there is no Birmingham to Glasgow service at all at the moment...

I cannot see any sensible way that a through full-width gangwayed EMU can be splittable in service without adding significant operating difficulties, which would far outweigh any theoretical energy saving.

== Doublepost prevention - post automatically merged: 3 Apr 2022 ==

the computer used every watt of it leaving St P!

But that burst of power would be curtailed when the train had reached the linespeed (I imagine 50mph on the incline to Kentish Town and through the ladder at Carlton Road junction) and holding 100mph, beyond Elstree tunnel would probably need far less than full power.

 

[AndrewE]

I cannot see any sensible way that a through full-width gangwayed EMU can be splittable in service without adding significant operating difficulties, which would far outweigh any theoretical energy saving.

== Doublepost prevention - post automatically merged: 3 Apr 2022 ==

The Danish/Swedish Oresund trains
https://en.wikipedia.org/wiki/Øresundståg clearly do not work then.

 

[Lucan]

Less trains

running fewer trains is clearly one possible answer to that, albeit not one that is necessarily desirable. (Although it might be on some lightly used services, such as my 5MW train home last night that had about 30 people on it.)

It is a fallacy to think that if (for example) you get 30 passengers on half-hourly trains then by reducing them to hourly (halving costs) you would get 60 passengers on each train. What really happens is that most people will go by car instead and probably you will get only 15 passengers on your hourly train. It is not a captive market as both accountants and striking workers have wrongly assumed in all sorts of industries in the past, over and over again.

I have lived in the sticks and there was a mini-bus service along my road into town 15 miles away. I'd have loved to use it, but In 10 years I never did, because every time I considered it (eg to visit the dentist) and looked at the time table, I found it almost useless. It seemed to be geared to school times, and in between there were intervals of up to three hours. It would have left me kicking my heels at the town end for anything up to four hours, or having to get an expensive taxi back home. So I drove instead.

 

[Bald Rick]

But that burst of power would be curtailed when the train had reached the linespeed (I imagine 50mph on the incline to Kentish Town and through the ladder at Carlton Road junction) and holding 100mph, beyond Elstree tunnel would probably need far less than full power.

oh it reached ATO linespeed (50kph) within a few hundred metres.

== Doublepost prevention - post automatically merged: 3 Apr 2022 ==

It is a fallacy to think that if (for example) you get 30 passengers on half-hourly trains then by reducing them to hourly (halving costs) you would get 60 passengers on each train. What really happens is that most people will go by car instead and probably you will get only 15 passengers on your hourly train.

I didn’t suggest it was, although there is very strong evidence on most flows that reducing frequency by % does not reduce passenger numbers by the same amount. Or, looking at it the other way, doubling frequency does not double passenger numbers.

again, not that I am advocating it.

 

[zwk500]

It is a fallacy to think that if (for example) you get 30 passengers on half-hourly trains then by reducing them to hourly (halving costs) you would get 60 passengers on each train. What really happens is that most people will go by car instead and probably you will get only 15 passengers on your hourly train. It is not a captive market as both accountants and striking workers have wrongly assumed in all sorts of industries in the past, over and over again.

I didn't suggest you would. The question was how to reduce energy. In the climate crisis we are currently facing, less rail passengers might be something that has to be accepted. Not all will make the journey by car - remote working is changing the way people travel, and the rail industry will need to adapt to that reality. Equally likely is that travel to big shopping centres will decrease (it wasn't a big market but did have a fair chunk of some flows) as people shop online even more.

I have lived in the sticks and there was a mini-bus service along my road into town 15 miles away. I'd have loved to use it, but In 10 years I never did, because every time I considered it (eg to visit the dentist) and looked at the time table, I found it almost useless. It seemed to be geared to school times, and in between there were intervals of up to three hours. It would have left me kicking my heels at the town end for anything up to four hours, or having to get an expensive taxi back home. So I drove instead.

At the risk of poking a bear, I would suggest then that public transport was doing exactly what it needed to - you had a car and were the only one making your journey, but the schoolkids didn't and there were lots of them heading for the same place. To have run a bus every hour (say) to give you a frequent enough timetable to use the service would have been wasteful of diesel, buses, drivers and cash as there are only a few people making a handful of trips per week to very different destinations. Public transport can't serve individual cottages on a country lane effectively. It shouldn't even try.