Reason to pick US standard gauge?
peter_kokh
preexisting infrastructure (including bridges), the question of track
gauge with is wide open. Reasons to pick a gauge wider, even
substantially wider, include low gravity with standard momentum. The
wider the gauge the lower the relative center of gravity, and the more
derailment resistant trains will be.
On the other hand, as RR car "trucks" or "bogies" are something that
may have to be imported in the near term, standard US trucks or
bogies, even reconditioned used ones, will be cheaper than anything
specially made.
Yet the purchase cost of a railcar truck is minimal in comparison to
the cost of fuel to get it to the Moon and Mars. But the wider and
probably more massive a truck, the more fuel it will take to get it to
its destination. So there are a lot of factors to way: safety vs.
cost, especially. Given that derailment of a pressurized passenger car
would probably breach seals and thus not be survivable, I'm still in
favor of wider gauges.
And given that pressurization could probably not be maintained in a
vestibulated passenger train while under way, with the vestibules
constantly twisting and turning and shaking, a wider gauge may allow
cars with more passenger capacity, thus reducing the need or desire to
connect them by pressurized flexible vestibules.
Another negative, however, is that the wider the gauge, the costlier
the RR ties that keep the rails properly spaced. But we can't
determine that cost factor yet, as we are a ways from indentifying
good material options for RR ties. No wood on the Moon or Mars, of
course.
Arthur Smith
Another thought - the standard gauge width is the main limit to the
size of easily transported objects on land; larger items have to be
transported by water or require roads to be closed while they go
through; water obviously isn't an option on Moon or Mars either. And
that limit makes it very inconvenient to transport a range of useful
objects from houses to large rocket components...
So I think at least doubling the standard gauge would be a good step
for our new planetary homes!
Arthur
James Gholston
Q1: How much does width impact turning radius?
Q2: For transportation, might we design the cars and engines with an
extended wheelbase that can be retracted for transportation, then fully
extended on site? The main problem I can think of at the moment is that
it may adversely impart the maximum mass they might be able to safely
carry, but this could get us started with a target wheelbase immediately
in a forwards compatible design that will be fully taken advantage of
when shipping from Earth isn't a consideration anymore.
James Gholston
Bryan Bishop
> Q1: How much does width impact turning radius?
A good question, but there's a lot of space to put excessively wide
turns, especially for training, as long as it doesn't conflict with the
minimal distance between two stops.
> Q2: For transportation, might we design the cars and engines with an
> extended wheelbase that can be retracted for transportation, then
> fully extended on site? The main problem I can think of at the
> moment is that it may adversely impart the maximum mass they might be
> able to safely carry, but this could get us started with a target
> wheelbase immediately in a forwards compatible design that will be
> fully taken advantage of when shipping from Earth isn't a
> consideration anymore.
Another idea might be to use a reconfigurable wheelbase and
reconfigurable track system. I see no reason why there can't be a
mechanical design allowing for this feature. Actually, I don't
understand the problem all that well; is the issue that the majority of
carts are hypothesized to not be liftable or something? Why not just
include portable lifting equipment, mechanical arms and whatever else
is needed ? Then you just use a base that is balanced, and one that can
follow the outlined path, no?
I think I missed the gravy train when it was discussed how much of
traditional railroading systems to keep and how much to throw away.
- Bryan
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