Frequency of Train Traffic v Interstate Traffic

[Bret Cahill]

The most heavily traveled rail lines are occupied by rolling rolling
stock only 5% of the time.

For most interstate traffic, at least near most cities, it's at least
twice - 3X as high.

This is particularly wasteful as the efficiencies of road vehicles are
so much lower than those of rail.


Bret Cahill

 

[John Larkin]

On Sun, 28 Dec 2008 20:52:45 -0800 (PST), Bret Cahill
<BretCahill@aol.com> wrote:

The most heavily traveled rail lines are occupied by rolling rolling
stock only 5% of the time.

For most interstate traffic, at least near most cities, it's at least
twice - 3X as high.

What's the definition of "occupied" as applied to an interstate
highway?

John

 

[Bret Cahill]

The most heavily traveled rail lines are occupied by rolling rolling
stock only 5% of the time.

For most interstate traffic, at least near most cities, it's at least
twice - 3X as high.

What's the definition of "occupied" as applied to an interstate
highway?

Safe following distance.

With 100% sedans packed in one lane, it comes out to 100 vehicles/
mile, each averaging 10 kW or 1 MW/mile.

Packed semi rigs would ave. 1.6 MW/mile.

A mile long train needs 24 MW and at 70 trains/day it's only 1.2 MW/
mile.

All three situations are in the same 1 - 1.6 MW ballpark as far as
power/mile.

Compare grid v. grid-battery costs/mile for 100 sedans:

$100/hr to power one mile of road directly from the grid without using
the battery.

$200/hr for batteries if grid-battery.

$300/hr total for grid-battery.

On a 24/7 basis that's $2.6 million/year-mile for grid-battery, 0.9
for the juice and 1.7 for the batteries.

In other words, powering vehicles directly from the road bed would
save commuters $1.7 million/mile-year in battery costs.

This would be possible to finance if electrification of two lanes was
less than $20 million/mile.

This doesn't necessarily mean batteries are eliminated -- something
will always be necessary when off the electric road -- just that the
savings from not having to constantly replace batteries justifies
electrification.

Electrification of roads would certainly open up some interesting
possibilities.

1. Hybrid and EV drive trains would require only a pick up and they
could still retain their high mpg off electric roads.

2. An aftermarket 10 -30kW electric motor could be added to
conventional gas guzzling drive trains. When on the electric freeway,
put the V-8 in neutral and run off the electric motor.

The real advantage of hybrid-air over hybrid electric is the _overall_
costs are much lower -- a cheap fiber wound pressure vessel can be
cycled 13 gazillion times -- but there isn't any easy way to supply
compressed air from the road to a moving vehicle. And the added
complexity / reduced efficiency of first running grid energy through a
compressor and then an expander may be an issue.

It may be better to start out with hybrid electric but no matter what
happens, there must be an electric motor somewhere in the vehicle
because we're just in the eye of the hurricane.

Obama seems serious about getting the economy going and when that
happens fuel prices will resume spiraling.

With a vengance.


Bret Cahill

 

[Eeyore]

Bret Cahill wrote:

The most heavily traveled rail lines are occupied by rolling rolling
stock only 5% of the time.

For most interstate traffic, at least near most cities, it's at least
twice - 3X as high.

In other words, the roads are typically much more useful at trasferring
people from A to B.

Graham