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Old May 28th, 2011, 10:47 AM   #41
XAN_
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Quote:
Originally Posted by aquaticko View Post
As was sort of touched on before, weight is also an issue with this method of power production. It's why nuclear-powered planes and (non-military, with the exception of some icebreakers) naval vessels never took off. For every extra pound of its own weight a vehicle has to move, there's a correspondant reduction in maximum payload capacity. The weight of all the shielding that would be necessary to make such a train passably safe would significantly reduce the weight of the cargo (or passengers) that could be moved at whatever speed, ergo reduced revenue.

As much as the pro-nuclear and retro-futurist in me loves the idea of nuke-powered everything, I can't disagree with the issues that others have brought up, issues that make that Googie dream unfeasible.

And btw Railfan, I love that poster.
Well, weight aren't so important for a railroad freight loco, especially with such a power onboard.
What really kills the entire idea - loading gauge. The reactor itself can be relatively small, but you still need a thick bioprotection to avoid personnel injury with a radiation. And making it crash resistant require it to be ever thicker.

Maybe if 3 000 m gauge back in 1940th would have been built, it could be possible, or maybe not, but sure not on classic gauges.
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Old May 28th, 2011, 11:47 AM   #42
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Weight does matter if it's loaded on limited amount of axles.
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Old May 28th, 2011, 11:49 AM   #43
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Imagine a rail accident!

Its probably best to have electric powered trains with the electric produced from nuclear at a power station.
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Old May 30th, 2011, 08:40 AM   #44
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Originally Posted by mgk920 View Post
Ahhhh, aren't many trains, especially in France, already nuclear-powered?

What percentage of France's electric power consumption comes from nuclear power plants?
78% (highest percentage in the world).

It's interesting that France's TGVs use a 25KV/50Hz AC power supply, which means that they can just tap in to the grid. In Germany and Switzerland the railways use 15KV 16.6Hz AC, and generate their own power.
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Old May 30th, 2011, 10:39 AM   #45
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Quote:
Originally Posted by K_ View Post
78% (highest percentage in the world).

It's interesting that France's TGVs use a 25KV/50Hz AC power supply, which means that they can just tap in to the grid. In Germany and Switzerland the railways use 15KV 16.6Hz AC, and generate their own power.
...it´s not completely true. In Germany only 1/3 are generated on their own. The rest is transformed from the normal 50Hz power supply.
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Old May 30th, 2011, 07:50 PM   #46
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Quote:
Originally Posted by K_ View Post
78% (highest percentage in the world).

It's interesting that France's TGVs use a 25KV/50Hz AC power supply, which means that they can just tap in to the grid. In Germany and Switzerland the railways use 15KV 16.6Hz AC, and generate their own power.
Just tap in to the grid, eh ? It's far more difficult than you imagine... The
grid is 3-phase, but you need single phase for a railway substation that feeds
a 25 kV-50 Hz catenary. So you basically tap one phase, sometimes two,
but almost never three. This is known to the electricians as an "unbalanced load"
which is something they hate because it creates them a shitload of
problems. There have been years of studies made by SNCF and EDF (the
french nationwide electricity production company) before declaring the
electrical version of the TFV feasable (the first version was turbine-powered).
It has only been possible 'cause the european electricity network is huge and
can tolerate such non balanced loads. For lighter networks, like in third-world
countries, this would be impossible. For electricians, direct-current traction is
much better, because you can generate direct current with a symmetrical
load, i.e. drawing the same current from the 3 phases at all times...
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Old May 30th, 2011, 09:08 PM   #47
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The 25kV/50Hz is still relatively simple because it is indeed so that the Power station that feeds the catanery is just connected to the AC grid, although you are correct that it just can't be connected on any random power connection.
Most DC power stations are powered on 15-70 kV nets, while AC stations are mostly powered on 150-380 kV nets, but this also has to do with the higher power of those stations.

Also don't forget that AC catanery has the advantage that there is a much larger area you can feed the power that is generated whet a train is using its regenerative brakes.
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Old May 31st, 2011, 07:37 PM   #48
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[QUOTE=pietje01;78716478Also don't forget that AC catanery has the advantage that there is a much larger area you can feed the power that is generated whet a train is using its regenerative brakes.[/QUOTE]

Provided that you have regenerative brakes in AC, which still remains an
exclusivity of the very recent rolling stock, because of the difficulty to
generate the current at the right frequency and in phase with the catenary.
There too, it is much easier to do it with DC traction.
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Old May 31st, 2011, 08:13 PM   #49
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Quote:
Originally Posted by MarcVD View Post
Provided that you have regenerative brakes in AC, which still remains an
exclusivity of the very recent rolling stock, because of the difficulty to
generate the current at the right frequency and in phase with the catenary.
There too, it is much easier to do it with DC traction.
Ahh, There were 11Kv/25Hz AC systems in use in North America in the early to mid 20th century that used regenerative braking - including one on a mountainous long-tunnel line in Washington State (operated from 1927-1956).

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Old May 31st, 2011, 11:15 PM   #50
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It is necessary that the Russians sends us the rendering and technical details of the trains nuecleares to end this discussion.
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