My idea for power to the train

[gerryuk]

Stupid question time or is it?
Could some sort of wind turbine be fixed to the roof of a train and produce enough power via a battery to power the train?
Obviously i am not talking about erecting a 150mtr pole with turbines on the end but could some sort of flat turbine be fitted above the drivers cab? Obviously there will be no problem with wind.
Regards

 

[dosxuk]

No. You would need a perpetual motion machine for this to work, and they can't exist in the real world.

 

[ilkestonian]

No. You would need a perpetual motion machine for this to work, and they can't exist in the real world.

Ah, but if the wind was blowing strongly enough...

 

[Nean]

No. You would need a perpetual motion machine for this to work, and they can't exist in the real world.

Indeed, the turbines themselves work by drag so it would create more work for the train to do and the resulting mechanical and electrical losses in the turbine would make it completely useless and a waste of energy instead of a way of recuperating

A more sensible idea would be to fit solar panels, however due to the amount of stuff on the roofs of most trains that would most likely be in the very heavy cost to little benefit due to the many inefficiencies in the system and refitting trains with them.

A sillier idea would be to have generator-connected Gym Bikes or Rowing Machines in "Gym Class" coaches for those who want to work out on the way to/from work...

 

[alex17595]

Ah, but if the wind was blowing strongly enough...

Or you had a fan?

 

[edwin_m]

As last seen on Wacky Races I think.

In theory a wind turbine on a train could still capture energy from the local wind rather than just the slipstream of the train, in sort of the same way that a yacht can use the power of the wind to sail upwind. However in practice this would almost certainly be lost due to inefficiencies in the system, and even if it wasn't the turbine needed to make any significant contribution to powering the train would be vast.

 

[asylumxl]

You'd be better off capturing energy elsewhere if you really want to generate electricity from a train.

 

[gerryuk]

Thanks for the responses, although I am not totally convinced.
I can see that powering a whole train from some sort of wind turbine on the roof would be a big ask. However lets say a 2 car train ran non stop from Sheffield to Manchester {plenty of wind in the Peaks} and it had some sort of flat turbine on the roof above the driver. Surly this would provide some sort of power to a battery, if only to power the lights in the carriages? As Tesco says ‘Every little helps’.

On a similar note what about Hybrid, Ethanol and Hydrogen Fuel Cell technology. I know they have been used on buses could trains be converted to use any of these?

 

[snowball]

Think of sailing ships. They were optimised to get power from the wind. They were much lighter than trains and had huge sails and even so were only able to go at a fraction of the speed.

Then there's the problem of fitting the turbine under bridges, or under the wires if the train happens to go along an electrified line.

 

[Peter Mugridge]

Or you had a fan?

That would not work; if the turbine had 100% efficiency - which it won't - it would require the capture of the full output from the fan in order to simply drive the fan at a constant speed. This would leave no energy available to puff the sail to move along.

 

[snowball]

That would not work; if the turbine had 100% efficiency - which it won't - it would require the capture of the full output from the fan in order to simply drive the fan at a constant speed. This would leave no energy available to puff the sail to move along.

That's already been expressed by the remarks about perpetual motion machines.

Might work if we lived on Jupiter though, don't they have 1000mph winds there?

 

[Peter Mugridge]

That's already been expressed by the remarks about perpetual motion machines.

Might work if we lived on Jupiter though, don't they have 1000mph winds there?

It was, but the diagram was posted after those remarks wasn't it?

Jupiter.... ignoring the lack of a solid surface on which to build the railway yes, though with winds like that you wouldn't need to capture electrical power for traction ( only for auxiliaries ) - you could just have a relatively small rim around the front of the train like an extended rocket cone and use the wind power as traction.

Making the return journey without having to continue all the way round the planet might be more problematic, however!

 

[JamesRowden]

Stupid question time or is it?
Could some sort of wind turbine be fixed to the roof of a train and produce enough power via a battery to power the train?
Obviously i am not talking about erecting a 150mtr pole with turbines on the end but could some sort of flat turbine be fitted above the drivers cab? Obviously there will be no problem with wind.
Regards

The answer is: so long as there is another source connected to the system (e.g. electrified line, diesel generator), the energy recycled via the turbine could be transfered to the battery and later used to power the whole train, even if for no more than an instant. The turbine would be a form of regenerative airbrake and a way to transfer energy from the other sources to the batteries via air resistance.

However, transfering the power through the electrionic systems and the transmission system instead should be the more efficient approach.

 

[SpacePhoenix]

Wind wouldn't work as you'd sometimes get situations where the wind speed from the wind blowing it as the train moves and the normal wind will take the overall wind speed above the maximum that a turbine can handle so it'll either have to be shut down (leaving the train stuck somewhere or out-of-control (what happens with modern stock if the main power (electric or diesel) is lost when the train is moving - does the emergency brake kick in?) or the turbine breaks.

 

[gordonthemoron]

what about photovoltic cells on trains?

 

[ASharpe]

I think the weight of the turbines or batteries and whatever else might also be an issue. The cost in energy of frequently getting them up to speed and dragging them up hills would probably outweigh the benefit. This is in addition to problems going into the wind.

However if the wind turbines could be kept is some stationary position that is suitably windy (e.g. a siding next to a high speed line) and the energy transferred some other way to the train we might be onto a winner.

The issue of transferring the power would still need to be solved, perhaps using high power lasers or microwave technology. Or if the energy loss in converting to light and back are two much then maybe the electricity could be supplied by some of wire.

I have a 50m extension lead that isn't too big, perhaps a few could be run behind the train to supply the power for acceleration.

Eventually the idea could be developed to be able to supply wind, solar or nuclear power to the entire network via some complex system of wires or other conductor.

 

[Flamingo]

I'm reminded of a line I heard once "First class out and walk, Second class out and push!"

 

[gerryuk]

Well the title of this thread has been changed (not by me) to ‘MY IDEA’ to power the train. Well it’s not my idea. I was simply asking the question if it is possible to put wind turbines on the top of trains to harness the energy from the wind.
Most have dismissed the idea, however -
http://www.cibtech.org/J ENGINEERING TECHNOLOGY/PUBLICATIONS/2011/Vol 1 No. 1/20-16-jet-DWIVEDI.pdf

 

[starrymarkb]

Or you had a fan?

Reminds me of a Coyote, Rollerskates, An outboard motor, a bath and a kids cart and some dubious but very funny physics

http://youtu.be/8H41zbqrwVo?t=2m4s

 

[gerryuk]

I think the weight of the turbines or batteries and whatever else might also be an issue. The cost in energy of frequently getting them up to speed and dragging them up hills would probably outweigh the benefit. This is in addition to problems going into the wind.

However if the wind turbines could be kept is some stationary position that is suitably windy (e.g. a siding next to a high speed line) and the energy transferred some other way to the train we might be onto a winner.The issue of transferring the power would still need to be solved, perhaps using high power lasers or microwave technology. Or if the energy loss in converting to light and back are two much then maybe the electricity could be supplied by some of wire.

I have a 50m extension lead that isn't too big, perhaps a few could be run behind the train to supply the power for acceleration.

Eventually the idea could be developed to be able to supply wind, solar or nuclear power to the entire network via some complex system of wires or other conductor.

http://theenergycollective.com/davi...al-will-determine-if-future-rail-wind-powered

 

[Darandio]

Well the title of this thread has been changed (not by me) to ‘MY IDEA’ to power the train. Well it’s not my idea.

They like to do that.

 

[AndyNLondon]

what about photovoltic cells on trains?

There's nowhere near enough space on a train roof for PV to power a train. Some examples of peak power output for UK installations are 100w/m² (CIS Tower, Manchester) - 160W/m² (domestic rooftop, Cambridge), with averages obviously a lot less - the Cambridge example quotes 20W/m² average.

A train carriage might have about 50m² of roof space (assuming 20m x 2.5m - most are slightly bigger than that, I know, but not all the roof space will be usable - and round numbers make the sums easy ), so being generous and assuming 160W/m² you could peak at 8kW from each carriage roof. From Wikipedia (yeah, I know) the lowest power consumption around for an EMU is a class 315 at 656kW for 4 carriages i.e. 164kW/carriage, so 8kW of PV on the roof won't go very far.

(Of course, if you get rid of all that pesky (heavy) bodywork and only want to go at 25km/h, a company in Budapest might have just the thing!)

 

[sutty]

There's nowhere near enough space on a train roof for PV to power a train. Some examples of peak power output for UK installations are 100w/m² (CIS Tower, Manchester) - 160W/m² (domestic rooftop, Cambridge), with averages obviously a lot less - the Cambridge example quotes 20W/m² average.

A train carriage might have about 50m² of roof space (assuming 20m x 2.5m - most are slightly bigger than that, I know, but not all the roof space will be usable - and round numbers make the sums easy ), so being generous and assuming 160W/m² you could peak at 8kW from each carriage roof. From Wikipedia (yeah, I know) the lowest power consumption around for an EMU is a class 315 at 656kW for 4 carriages i.e. 164kW/carriage, so 8kW of PV on the roof won't go very far.

(Of course, if you get rid of all that pesky (heavy) bodywork and only want to go at 25km/h, a company in Budapest might have just the thing!)

With that, you'd probably lose those electrical gains due to the weight of the panels.

 

[GB]

Its possible to use air resistance to give certain power to certain electronic systems, aviation has been doing it for years for emergency power for flight systems. You will never get enough power to actually move the train though and the speed of the train will determine amount of electricity produced from the prop.

 

[Bill Stanier]

So, there's this aeroplane taking off from a runway that's a conveyor belt. The faster the aeroplane moves forward, the faster the belt moves backwards.

Can the aeroplane ever take off?

Not a rail question, but given some of the posts on here I'd be interested in the answers...

 

[Trog]

So, there's this aeroplane taking off from a runway that's a conveyor belt. The faster the aeroplane moves forward, the faster the belt moves backwards.

Can the aeroplane ever take off?

Not a rail question, but given some of the posts on here I'd be interested in the answers...

Yes the only difference from normal is that there will be a slight increase in the friction generated in the wheel bearings as the wheels will be rotating twice as fast as normal.

 

[GB]

So, there's this aeroplane taking off from a runway that's a conveyor belt. The faster the aeroplane moves forward, the faster the belt moves backwards.

Can the aeroplane ever take off?

Not a rail question, but given some of the posts on here I'd be interested in the answers...

If the treadmill is moving at such as speed as to make the aircraft stationary then no it will not take off as there will be no air flow and no lift over and under the wings.

 

[Bill Stanier]

Trog has the correct answer. The treadmill can go as fast as it likes, it'll make no difference except to make the aeroplane's wheels rotate faster (discounting such practicalities as the wheel bearings siezing up if they overspeed too much).

The aeroplane isn't being accelerated through its wheels like a land vehicle, it is using thrust from a propeller or a jet engine, and that thrust makes the aeroplane accelerate regardless of the rearwards-moving runway.

 

[Stompehh]

So where does the lift come from?

 

[JB_B]

I think the critics who've suggested that this would be analogous to a perpetual motion machine have got the wrong end of the stick. There is energy that can be harvested - - see e.g. http://en.wikipedia.org/wiki/Vestas_Sailrocket - the problems are collecting enough of it (very low relative energy availability) and storing it efficiently to give any sort of usable service (the losses after that are the same for traction system).

The Bhopal academics (in the paper cited) - who possibly weren't being entirely serious - were only suggesting powering the lights and coach fans - not traction.