Posted By: Water SystemsDiesels are not more efficient because the compression ratio is higher. Modern injcetd engiens with management system beat the diesels.

You're wrong, I'm afraid. Diesels are more efficient precisely because of the higher compression ratio, lower parasitic losses (no throttle) and higher combustion temperatures (this in itself leads to higher Carnot efficiency). It's not the appearance of higher efficiency, it's reality. If gasoline engines were more efficient they'd be used for trains and trucks. As for pollution, this can be solved for any internal combustion engine. I suggest you read up on the Carnot cycle and heat engines in general if you don't believe me.

Posted By: Water Systems00% electric, including inefficient transmission losses.

Transmission is not inefficient. Why don't you read up on state of the art HVDC transmission before you perpetuate this myth? All these basic factual errors detract from your otherwise good arguments - which I actually agree with.

Paul in Montreal.

Posted By: Water SystemsYou don't seem to gasp the energy in to the power station and energy available at point of burn for electrical power generation

And you don't seem to grasp that powerstations that burn stuff to make electricity are going to have to be replaced if we are to stop using fossil fuels. Over here, all our wagon train is electrical with the starting point hydroelectricity. End-to-end is about 65-70% of the potential energy of the water delivered to the end customer, transmission and conversion losses included. You guys will have no choice but to replace all your fossil fuel stations with something else, be it long distance HVDC from Iceland or from the solar installations going into North Africa.

For transport, I completely agree with you that an electrical solution is the best bet. With a distributed storage system this allows uneven generation through renewables to work effectively - of course this storage could be tidal lagoons as you point out (though these are not without their environmental costs) or ultracapacitors/batteries etc. For things like trains, the weight of the engine is irrelevant as it's tiny compared to the payload so it's better to use the most efficient solution available. As for soot, it's also solvable - all internal combustion engines produce pollutants that have to be dealt with - the only thing that has driven this is legislation.

Paul in Montreal.

Trains are very ungreen compared to personal transport such as the below:

http://en.wikipedia.org/wiki/Volkswagen_1-litre_car

Cars will drop in fuel consumption when the weight and air resistance comes down. The trouble is that governments and car companies have no incentive to do this.

I also think the velomobiles will be great especially when electric assisted:
http://greenash.net.au/sites/default/files/images/go_one_velomobile.jpg

There is one small issue with capacitors, and this is how to get round losses in charging of a capacitor. The energy in a cap is 1/2 * C * V * V. The other 1/2 of the energy got lost in the series resistance. So OK it may be possible to have a charging switcher to mitigate against this, but this will also have losses and will be expensive, especially for braking heavy loads.

Posted By: BrianRThe energy in a cap is 1/2 * C * V * V. The other 1/2 of the energy got lost in the series resistance.

Er, wrong. The 1/2 in that equation has nothing to do with half the energy. The series resistance of an ultracapacitor is pretty small - in fact, this makes them dangerous as that stored energy can be released very dramatically if they're shorted out for example.

Posted By: Water SystemsA six car electric urban train half full - approx 450 people, is a lot more green than 450 diesel VWs.

Definitely agree with this.

Paul in Montreal.

If all the people who used the trains reverted to using cars the pollution levels and traffic chaos would be appalling - look at some USA cities. Not to mention deaths and injuries by car accidents - trains are about the safest form of transport. Emission levels in centralised power plants can be easily and effectively controlled, unlike the millions of cars about. By their nature, passenger levels are busty. Off-peak trains can pull only one or two cars not whole train full, as they do in some networks

Use:

1. Light-rail trains
2. Brake regen
3. Clawback using supercapacitors
4. Stations were they should be,like in city centres underground.

Then the quality of life lifts, urban areas become more vibrant and pollution levels drop enormously.
I like animated train journeys. Maybe you need to improve your social skills and appreciation of community. :)

I was comparing like for like now, car VS train. Car comes off better (for me - not necessarily everyone).

For the future what would best best? A zero carbon transport system that got everyone to their destination in the fastest time with maximum comfort, or a zero carbon transport system that got everyone there a bit slower, and made them miserable. My assumption is that no one will design a mass transit system that picks me up from the end of my drive and drops me off within 400 yds of my workplace.

I know technology can't solve everything, but some examples I can think of: If cars are zero carbon, then the only thing wrong with congestion, is congestion. So you need to design a system to reduce congestion. Either take the driver out of the equation so that cars can do 60 mph bumper to bumper, and get rid of junctions that mean stopping. An automated roundabout which cars merged at 40mph should be feasible. Think of a localised traffic control system at every round about. Car users pay enough tax so should expect some serious improvements in the future. Cars don't have to weigh 1.5 tonnes. Look at the smart EV available for next year. (Made 5 miles from where I live) or the futuristic but real Aptera, capable of upto 1,000 mpg equivalent. 300 mpg is worse case. No train system can compare with that. They weigh too much and run when people don't use them.

I'm not suggesting ripping up mass transit in it's entirety. But review how each route is used, and whether is could be improved by changing the vehicle type. Sometimes commuter trains or trams are the best solution, especially when residients of a town or city are travelling to work in it's centre. However many people commute between towns, and it's these journeys that public transport is useless for. A big scheme I'd like to see in Birmingham is a park and ride placed at the outskirts of the M6/M5/M42 ring. Especially for visitors to the NEC ( I used to work next to it, and when big shows were on, I couldn't reverse out of my parking space at work!). There's dozens of suitable sites I've looked at, but don't have the capital, to set up such a scheme.

Of course best of all, would be not having to travel in the first place. A broadband connection and study with zoned heating system could be run for less that 1/10 the energy cost of commuting. Try telling that to large corporations/governments worried about data security though! My job should NOT need me to be present in an office. But never been able to homeworking yet.

The other solution would be lazer guided personal catapults. :-)

Simon.