Same with the Clipper card used in the San Francisco area. *A card can have both
passes and a cash balance for trips not covered by any of the passes. *It works
on seven different transit systems and can handle a baffling array of passes and
discount plans. *You can have a Muni monthly pass, and a BART High Value Discount
ticket which gives you $64 of BART credit for $60, as well as passes on other
systems and cash.

Is BART credit stored separately from otehr agencies' credit?

I haven't actually tried this, but it is my impression that if you add
$60 as BART credit, you get $64 good only on BART, while if you add
$60 as cash, you get $60 good on anything.

In the NYC region, the 7% Metrocard bonus when you load at least $10
applies to the credit you can use on any agency that takes Metrocard.

Right. I agree that makes more sense, but I suspect that the issue
with the Clipper is that the agencies just moved their existing fare
structure onto Clipper. The other agencies have their own pass
programs and probably aren't interested in funding BART's discount
plan.

R's,
John

On 30-Jan-12 23:40, Robert Bonomi wrote:
In article ,
Stephen Sprunk wrote:
On 30-Jan-12 17:37, Robert Bonomi wrote:
*HOWEVER*, tanks are *heavy* -- substantially surpassing the legal load
limits on most highways. An "M1A1", alone, NOT INCLUDING the weight of
the transporter vehicle, is close to double the legal weight limit on most
highways.

Load limits are specified per axle or tandem, and tank transporters have
_lots_ of axles to spread the tank's weight out.

Some are, some are *not*.

'More axles' doesn't make any difference to a bridge span. grin.

However, load limits are calculated based on a series of axles/tandems
at least 96 inches apart. How much do you want to bet that's how far
apart the five non-tandem axles on a modern tank transporter are?

Still, a loaded transporter still exceeds the per-axle/tandem load
limit, but not by a very large margin. If you restrict a convoy to
travel in single file and split two lanes, which would be a requirement
anyway due to being overwidth, a span would have _less_ loading than is
possible with normal trucks in those two lanes. And that's just static
loading; once you figure in dynamic loading, the lower speed probably
means even that isn't strictly necessary.

S

--
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking

On 30-Jan-12 21:39, Adam H. Kerman wrote:
Stephen Sprunk wrote:
On 29-Jan-12 17:57, Adam H. Kerman wrote:
Stephen Sprunk wrote:
On 29-Jan-12 14:09, wrote:
On Jan 29, 11:07 am, Stephen Sprunk wrote:
Movement of tanks. That is the origin of the clearance, lane width and
bridge-strength requirements--and in turn limits the height, width and
weight of new US tanks.

I'm not sure that's true. Tanks are not very kind to concrete roadway
surfaces, nor do they move very fast, and of course drink up fuel. I
would think if tanks have to be moved any sort of distance they would
be loaded onto trains.

The tanks would not be directly on the roadway unless they were actually
deployed for battle on US soil, in which case I doubt anyone would care
about what it did to the pavement.

Otherwise, the tanks would be on transporters, which is why the
Interstate vertical clearance requirements are so high.

Transport is designed to current standards, not the other way around.

The "standards" of the day varied significantly from state to state and
were, in many places, completely insufficient for the Army's needs. The
entire purpose of the Interstate system was to unify and raise those
standards _to match the transport needs_.

Here in Chicago, which may have more elevated railroads than anywhere
else, the required elevation standard was based on trucks of that era.

It sounds like you're asking about civilian trucks, which are completely
irrelevant to the discussion; we're discussing highway standards to meet
_military_ needs.

Why would any state have had lower vertical clearance standards than
required for trucks of that era?

Because the local (not even state, at that point) authorities had no
reason to spend extra money building bridges and such to handle military
equipment that, until that point, had never attempted to use them.

Why do you think it took Lt. Eisenhower two months to cross the country?

Were there any significant number of trucks sold that exceeded 12' 6",
a common vertical height limit prior to 1956? Expressways in my area
prior to 1956 didn't have 13' 6" clearances until they were reconstructed.

I've seen bridges with clearances under 10ft. And it's not just about
height; it's also about width and weight.

In theory, the Army _could_ have tried to redesign their tanks, etc. to
the size, height and weight of a Model T or horse-drawn wagon--what much
of the US road infrastructure of the day could handle--but they probably
wouldn't have fared too well in battle.

Now you're moving the goal posts from vertical clearance to weight

Moving the goalposts? Look at the very first quote at the top of this
thread, Adam. You're the one that focused only on height; the rest of
us have been talking about _all_ dimensions.

The concept that roads and bridges would be designed for trucks that
don't exist is awfully odd.

The trucks _did_ exist: in the Army.

S

--
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking

Stephen Sprunk wrote:
On 30-Jan-12 21:39, Adam H. Kerman wrote:
Stephen Sprunk wrote:
On 29-Jan-12 17:57, Adam H. Kerman wrote:
Stephen Sprunk wrote:
On 29-Jan-12 14:09, wrote:
On Jan 29, 11:07 am, Stephen Sprunk wrote:
Movement of tanks. That is the origin of the clearance, lane width and
bridge-strength requirements--and in turn limits the height, width and
weight of new US tanks.

I'm not sure that's true. Tanks are not very kind to concrete roadway
surfaces, nor do they move very fast, and of course drink up fuel. I
would think if tanks have to be moved any sort of distance they would
be loaded onto trains.

The tanks would not be directly on the roadway unless they were actually
deployed for battle on US soil, in which case I doubt anyone would care
about what it did to the pavement.

Otherwise, the tanks would be on transporters, which is why the
Interstate vertical clearance requirements are so high.

Transport is designed to current standards, not the other way around.

The "standards" of the day varied significantly from state to state and
were, in many places, completely insufficient for the Army's needs. The
entire purpose of the Interstate system was to unify and raise those
standards _to match the transport needs_.

Here in Chicago, which may have more elevated railroads than anywhere
else, the required elevation standard was based on trucks of that era.

It sounds like you're asking about civilian trucks, which are completely
irrelevant to the discussion; we're discussing highway standards to meet
_military_ needs.

God you are unbelievably thick. Army trucks that use civilian roads are
designed to travel on civilian roads. There is no other standard.

Why would any state have had lower vertical clearance standards than
required for trucks of that era?

Because the local (not even state, at that point) authorities had no
reason to spend extra money building bridges and such to handle military
equipment that, until that point, had never attempted to use them.

Why do you think it took Lt. Eisenhower two months to cross the country?

I'm sure it had nothing to do with vertical clearance. They weren't
planning to cross Chicago. It had to do with fording streams, likely.

Were there any significant number of trucks sold that exceeded 12' 6",
a common vertical height limit prior to 1956? Expressways in my area
prior to 1956 didn't have 13' 6" clearances until they were reconstructed.

I've seen bridges with clearances under 10ft. And it's not just about
height; it's also about width and weight.

Uh, great. We've all seen such bridges. They were built for cars, not
trucks of any era.

not reading any more

Robert Bonomi wrote:
Stephen Sprunk wrote:

Load limits are specified per axle or tandem, and tank transporters have
_lots_ of axles to spread the tank's weight out.

Some are, some are *not*.

'More axles' doesn't make any difference to a bridge span. grin.

Can you expound on that? Bridges have a rated weight limit. If truck
weight is at the limit, why wouldn't the bridge benefit from improved
live load weight distribution, particularly if truck length exceeds
span length?

On 01-Feb-12 14:33, Adam H. Kerman wrote:
Stephen Sprunk wrote:
On 30-Jan-12 21:39, Adam H. Kerman wrote:
Stephen Sprunk wrote:
On 29-Jan-12 17:57, Adam H. Kerman wrote:
Stephen Sprunk wrote:
On 29-Jan-12 14:09, wrote:
On Jan 29, 11:07 am, Stephen Sprunk wrote:
Movement of tanks. That is the origin of the clearance, lane width and
bridge-strength requirements--and in turn limits the height, width and
weight of new US tanks.

I'm not sure that's true. Tanks are not very kind to concrete roadway
surfaces, nor do they move very fast, and of course drink up fuel. I
would think if tanks have to be moved any sort of distance they would
be loaded onto trains.

The tanks would not be directly on the roadway unless they were actually
deployed for battle on US soil, in which case I doubt anyone would care
about what it did to the pavement.

Otherwise, the tanks would be on transporters, which is why the
Interstate vertical clearance requirements are so high.

Transport is designed to current standards, not the other way around.

The "standards" of the day varied significantly from state to state and
were, in many places, completely insufficient for the Army's needs. The
entire purpose of the Interstate system was to unify and raise those
standards _to match the transport needs_.

Here in Chicago, which may have more elevated railroads than anywhere
else, the required elevation standard was based on trucks of that era.

It sounds like you're asking about civilian trucks, which are completely
irrelevant to the discussion; we're discussing highway standards to meet
_military_ needs.

God you are unbelievably thick. Army trucks that use civilian roads are
designed to travel on civilian roads. There is no other standard.

There _were_ no civilian highway standards at the time, Adam. The Army
wisely designed their combat equipment for the combat environment, not
for easy transportation on civilian roads of unspecified standards.

The solution chosen was to improve highways to meet the Army's needs,
not to downgrade the Army's military capabilities.

S

--
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking

Stephen Sprunk wrote:
On 01-Feb-12 14:33, Adam H. Kerman wrote:
Stephen Sprunk wrote:
On 30-Jan-12 21:39, Adam H. Kerman wrote:
Stephen Sprunk wrote:
On 29-Jan-12 17:57, Adam H. Kerman wrote:
Stephen Sprunk wrote:
On 29-Jan-12 14:09, wrote:
On Jan 29, 11:07 am, Stephen Sprunk wrote:

Movement of tanks. That is the origin of the clearance, lane
width and bridge-strength requirements--and in turn limits the
height, width and weight of new US tanks.

I'm not sure that's true. Tanks are not very kind to concrete roadway
surfaces, nor do they move very fast, and of course drink up fuel. I
would think if tanks have to be moved any sort of distance they would
be loaded onto trains.

The tanks would not be directly on the roadway unless they were actually
deployed for battle on US soil, in which case I doubt anyone would care
about what it did to the pavement.

Otherwise, the tanks would be on transporters, which is why the
Interstate vertical clearance requirements are so high.

Transport is designed to current standards, not the other way around.

The "standards" of the day varied significantly from state to state and
were, in many places, completely insufficient for the Army's needs. The
entire purpose of the Interstate system was to unify and raise those
standards _to match the transport needs_.

Here in Chicago, which may have more elevated railroads than anywhere
else, the required elevation standard was based on trucks of that era.

It sounds like you're asking about civilian trucks, which are completely
irrelevant to the discussion; we're discussing highway standards to meet
_military_ needs.

God you are unbelievably thick. Army trucks that use civilian roads are
designed to travel on civilian roads. There is no other standard.

There _were_ no civilian highway standards at the time, Adam.

The "standard" was bridges and clearances that existed on public
highways. For the 27th time, these bridges and clearances were
designed to trucks and traffic of the era they were built in for
local traffic needs, not anticipating trucks of the future, not
antipating Army convoys.

The Army wisely designed their combat equipment for the combat
environment, not for easy transportation on civilian roads of unspecified
standards.

Good thing combat environments have higher standard truck weight and
width tolerances.

The solution chosen was to improve highways to meet the Army's needs,
not to downgrade the Army's military capabilities.

Bull****. If it were not anticipated that a large number of trucks FOR
CIVILIAN PURPOSES would ply the nation's highways, they wouldn't have
written standards to accomodate them. Interstates weren't built
for the United States Army.

Do get started on that book you are writing.

Looks like John Levine continues to pester me with replies in email.
His latest reply was utterly incoherent, so it's no wonder he refused
to post an article to Usenet.

I suppose his immaturity has reached the level at which I'll have to
write a procmail recipie. I really don't like doing that as normally
I don't mind if people contact me. I feel sorry for him.

"John Levine" wrote in message
...
Any talks or projects for underwater tunnels between any of the Aleutian
Islands?

The largest "city" on the Aleutians is Dutch Harbor, pop. 4000. What
do you think?

Nord Kapp, population 3,224 has one, so what's the problem?

tim

In article ,
Adam H. Kerman wrote:
Robert Bonomi wrote:
Stephen Sprunk wrote:

Load limits are specified per axle or tandem, and tank transporters have
_lots_ of axles to spread the tank's weight out.

Some are, some are *not*.

'More axles' doesn't make any difference to a bridge span. grin.

Can you expound on that? Bridges have a rated weight limit. If truck
weight is at the limit, why wouldn't the bridge benefit from improved
live load weight distribution, particularly if truck length exceeds
span length?

An extreme case -- if the static weight of the vehicle exceeds the load at
which the span will collapse, and the span is longer than the wheelbase, it
doesn't matter whether it's a unicycle, or has wheels every 2 ft.

Or, consider a short span, just under the vehicle wheelbase. You can move
a two-axle load over that span that is nearly twice the 'collapse' loading,
because only half the load will be on the span at any time. Add a 3rd
axle, at the midpoint, and the total load on the span goes -up-.


Also, bridge spans, in general, tend to have a 'crown' along the length of
the span, as well as the side-to-side crowning. A side effect of that
longitudinal crowning is that interior axles carry somewhat more weight
than leading/trailing ones.

Robert Bonomi wrote:
Adam H. Kerman wrote:
Robert Bonomi wrote:
Stephen Sprunk wrote:

Load limits are specified per axle or tandem, and tank transporters have
_lots_ of axles to spread the tank's weight out.

Some are, some are *not*.

'More axles' doesn't make any difference to a bridge span. grin.

Can you expound on that? Bridges have a rated weight limit. If truck
weight is at the limit, why wouldn't the bridge benefit from improved
live load weight distribution, particularly if truck length exceeds
span length?

An extreme case -- if the static weight of the vehicle exceeds the load at
which the span will collapse, and the span is longer than the wheelbase, it
doesn't matter whether it's a unicycle, or has wheels every 2 ft.

Yes, I see your point on that.

Or, consider a short span, just under the vehicle wheelbase. You can move
a two-axle load over that span that is nearly twice the 'collapse' loading,
because only half the load will be on the span at any time. Add a 3rd
axle, at the midpoint, and the total load on the span goes -up-.

Yes, I see your point on that as well.

Also, bridge spans, in general, tend to have a 'crown' along the length of
the span, as well as the side-to-side crowning. A side effect of that
longitudinal crowning is that interior axles carry somewhat more weight
than leading/trailing ones.

Ok.

But what about the way spans are designed to flex? There are several
trigonometric formulas that apply (that I never learned). Aren't there
instances in which the same live load on various wheelbases can positively
or negatively impact the span's flexibility by creating different kinds
of deflection?