Safer Driving Through Science Fiction
Surely, issues like traffic jams, speeding, and road rage can be
solved through these creative strategies...
https://reactormag.com/safer-driving-through-science-fiction/
Safer Driving Through Science Fiction
Surely, issues like traffic jams, speeding, and road rage can be
solved through these creative strategies...
https://reactormag.com/safer-driving-through-science-fiction/
Safer Driving Through Science Fiction
Surely, issues like traffic jams, speeding, and road rage can be
solved through these creative strategies...
https://reactormag.com/safer-driving-through-science-fiction/
jdnicoll@panix.com (James Nicoll) writes:
Safer Driving Through Science Fiction
Surely, issues like traffic jams, speeding, and road rage can be
solved through these creative strategies...
https://reactormag.com/safer-driving-through-science-fiction/
Then there is the ultimate in driving safety, from Niven's story _Safe
at any Speed_:
"In the year 3100, thanks to fail-safe technology and the influence of
the Teela Brown Luck gene, in Known Space you have nothing to fear
except inconveniencerCoeven when your car is swallowed by a giant Roc."
http://www.larryniven.net/?q=bibliographic-reference/safe-at-any-speed
--
-Don_from_AZ-
https://reactormag.com/safer-driving-through-science-fiction/
Safer Driving Through Science Fiction
Surely, issues like traffic jams, speeding, and road rage can be
solved through these creative strategies...
(excerpt)
DREAM MASTER by Zelazny
"In the year 3100, thanks to fail-safe technology and the influence
of the Teela Brown Luck gene, in Known Space you have nothing to
fear except inconveniencerCoeven when your car is swallowed by a giant
Roc."
I remember a short story about a future world where the flow of
traffic became the absolute topmost priority. Everything else had to
give way to that: there were highways in all directions, stacked level
upon level, cutting through high-rise buildings where necessary. There
were regulations on minimum speed and maximum following distance, to
try to pack the traffic as efficiently as possible. Helicopters would
drop paint-bombs to mark vehicles moving too slowly, for later
enforcement action.
This does not sound like a science fiction story. This sounds like
Los Angeles today. Perhaps you were reading the "Guide to LA
Freeways."
On 6/20/2026 2:50 PM, Scott Lurndal wrote:
kludge@panix.com (Scott Dorsey) writes:
In article <3xyZR.6$Rg34.3@fx11.iad>, Scott Lurndal <slp53@pacbell.net> wrote:
Nuno Silva <nunojsilva@invalid.invalid> writes:
On 2026-06-20, Lawrence DrCOOliveiro wrote:Constant RPM. Electric power generated but not used for traction
On Fri, 19 Jun 2026 08:50:51 -0400 (EDT), Scott Dorsey wrote:Do you mean the speed at which energy is generated or something else? >>>>
... like a diesel-electric locomotive.
I like diesel-electric locomotives. The diesel does what it does best >>>>>> (run at a nearly constant speed), while the electrics do what they do >>>>>
or auxiliary power needs is dissipated as heat.
But that's not much loss because the engine doesn't take much fuel to
keep a constant speed when unloaded... as the load increases the fuel
demand goes up.
There's also dynamic braking to consider, where the electricity
generated by the traction motors while braking is dissipated as
well. The heat sinks (resistor grids) on those DE locos aren't small.
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
On 2026-06-21, Cryptoengineer wrote:
On 6/20/2026 2:50 PM, Scott Lurndal wrote:
kludge@panix.com (Scott Dorsey) writes:
In article <3xyZR.6$Rg34.3@fx11.iad>, Scott Lurndal <slp53@pacbell.net> wrote:
Nuno Silva <nunojsilva@invalid.invalid> writes:
On 2026-06-20, Lawrence DrCOOliveiro wrote:Constant RPM. Electric power generated but not used for traction
On Fri, 19 Jun 2026 08:50:51 -0400 (EDT), Scott Dorsey wrote:Do you mean the speed at which energy is generated or something else? >>>>
... like a diesel-electric locomotive.
I like diesel-electric locomotives. The diesel does what it does best >>>>>> (run at a nearly constant speed), while the electrics do what they do >>>>>
or auxiliary power needs is dissipated as heat.
But that's not much loss because the engine doesn't take much fuel to
keep a constant speed when unloaded... as the load increases the fuel
demand goes up.
There's also dynamic braking to consider, where the electricity
generated by the traction motors while braking is dissipated as
well. The heat sinks (resistor grids) on those DE locos aren't small.
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art
on these?
On 2026-06-21, Cryptoengineer wrote:
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's >experimental is storing in a battery.
Nuno Silva <nunojsilva@invalid.invalid> posted:
On 2026-06-21, Cryptoengineer wrote:
On 6/20/2026 2:50 PM, Scott Lurndal wrote:
kludge@panix.com (Scott Dorsey) writes:
In article <3xyZR.6$Rg34.3@fx11.iad>, Scott Lurndal <slp53@pacbell.net> wrote:
Nuno Silva <nunojsilva@invalid.invalid> writes:
On 2026-06-20, Lawrence DrCOOliveiro wrote:Constant RPM. Electric power generated but not used for traction
On Fri, 19 Jun 2026 08:50:51 -0400 (EDT), Scott Dorsey wrote:Do you mean the speed at which energy is generated or something else? >>>>>>
... like a diesel-electric locomotive.
I like diesel-electric locomotives. The diesel does what it does best >>>>>>>> (run at a nearly constant speed), while the electrics do what they do >>>>>>>
or auxiliary power needs is dissipated as heat.
But that's not much loss because the engine doesn't take much fuel to >>>>> keep a constant speed when unloaded... as the load increases the fuel >>>>> demand goes up.
There's also dynamic braking to consider, where the electricity
generated by the traction motors while braking is dissipated as
well. The heat sinks (resistor grids) on those DE locos aren't small.
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's
experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art
on these?
Add bank of capacitors.
https://www.ijsat.org/papers/2025/2/3360.pdf
Regards, ULF
Add bank of capacitors.
https://www.ijsat.org/papers/2025/2/3360.pdf
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
To do this with regen, you'd have to put motors/generators on
every axle on every car, which is expensive and impractical.
Cryptoengineer <petertrei@gmail.com> wrote:
Add bank of capacitors.
https://www.ijsat.org/papers/2025/2/3360.pdf
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
This is true of freight trains with one big powered locomotive pulling
lots of cars, but not true of subway trains where each car has its
own traction engine. But, subway trains also have external power which
makes regenerative braking by pumping current back into the mains possible.
To do this with regen, you'd have to put motors/generators on
every axle on every car, which is expensive and impractical.
Is it? You must take the A train! If! You want to go to Harlem!
--scott
But we were discussing diesel electrics, which aren't used on
the subway.
On 6/21/2026 5:16 AM, Ulf Kutzner wrote:[...]
Nuno Silva <nunojsilva@invalid.invalid> posted:
On 2026-06-21, Cryptoengineer wrote:
On 6/20/2026 2:50 PM, Scott Lurndal wrote:
There's also dynamic braking to consider, where the electricityEVs use regenerative braking, but dump the power back into the
generated by the traction motors while braking is dissipated as
well. The heat sinks (resistor grids) on those DE locos aren't small. >>>>
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's
experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art
on these?
Add bank of capacitors.
https://www.ijsat.org/papers/2025/2/3360.pdf
Regards, ULF
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
To do this with regen, you'd have to put motors/generators on
every axle on every car, which is expensive and impractical.
I don't know enough to say if it would be practical to let
the engine do much braking for the whole train.
Nuno Silva <nunojsilva@invalid.invalid> wrote:
On 2026-06-21, Cryptoengineer wrote:
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's >>experimental is storing in a battery.
You mean for electric locomotives rather than diesel-electric, and feeding the power back into the mains?
That would make sense but you need to
really trust your pantograph a lot because a small line dropout would mean
a brief but total loss of braking.
A shame there's no easy way to convert electricity to diesel.--
--scott
On 2026-06-21, Cryptoengineer wrote:
On 6/21/2026 5:16 AM, Ulf Kutzner wrote:[...]
Nuno Silva <nunojsilva@invalid.invalid> posted:
On 2026-06-21, Cryptoengineer wrote:
On 6/20/2026 2:50 PM, Scott Lurndal wrote:
There's also dynamic braking to consider, where the electricityEVs use regenerative braking, but dump the power back into the
generated by the traction motors while braking is dissipated as
well. The heat sinks (resistor grids) on those DE locos aren't small. >>>>
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's >>> experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art >>> on these?
Add bank of capacitors.
https://www.ijsat.org/papers/2025/2/3360.pdf
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
Note: it's applied air pressure that holds the brakes off, not the other
way around, that's what makes it fail-safe.
On 6/21/2026 5:16 AM, Ulf Kutzner wrote:
Nuno Silva <nunojsilva@invalid.invalid> posted:
On 2026-06-21, Cryptoengineer wrote:
On 6/20/2026 2:50 PM, Scott Lurndal wrote:
kludge@panix.com (Scott Dorsey) writes:EVs use regenerative braking, but dump the power back into the
In article <3xyZR.6$Rg34.3@fx11.iad>, Scott Lurndal <slp53@pacbell.net> wrote:
Nuno Silva <nunojsilva@invalid.invalid> writes:
On 2026-06-20, Lawrence DrCOOliveiro wrote:Constant RPM. Electric power generated but not used for traction >>>>>> or auxiliary power needs is dissipated as heat.
On Fri, 19 Jun 2026 08:50:51 -0400 (EDT), Scott Dorsey wrote: >>>>>>>>
... like a diesel-electric locomotive.
I like diesel-electric locomotives. The diesel does what it does best
(run at a nearly constant speed), while the electrics do what they do
Do you mean the speed at which energy is generated or something else? >>>>>>
But that's not much loss because the engine doesn't take much fuel to >>>>> keep a constant speed when unloaded... as the load increases the fuel >>>>> demand goes up.
There's also dynamic braking to consider, where the electricity
generated by the traction motors while braking is dissipated as
well. The heat sinks (resistor grids) on those DE locos aren't small. >>>
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's
experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art
on these?
Add bank of capacitors.
https://www.ijsat.org/papers/2025/2/3360.pdf
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
To do this with regen, you'd have to put motors/generators on
every axle on every car, which is expensive and impractical.
I don't know enough to say if it would be practical to let
the engine do much braking for the whole train.
Nuno Silva <nunojsilva@invalid.invalid> posted:[...]
On 2026-06-21, Cryptoengineer wrote:
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
Note: it's applied air pressure that holds the brakes off, not the other
way around, that's what makes it fail-safe.
Depends on where you are with what kind of train. https://en.wikipedia.org/wiki/Vacuum_brake#Present-day_use_of_vacuum_brakes
Cryptoengineer <petertrei@gmail.com> wrote:
Add bank of capacitors.
https://www.ijsat.org/papers/2025/2/3360.pdf
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
This is true of freight trains with one big powered locomotive pulling
lots of cars, but not true of subway trains where each car has its
own traction engine. But, subway trains also have external power which
makes regenerative braking by pumping current back into the mains possible.
Mulling over it, I think part of the problem is that while trainsIt'll become "practical" as soon as somebody finds a way to make money
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
To do this with regen, you'd have to put motors/generators on
every axle on every car, which is expensive and impractical.
I don't know enough to say if it would be practical to let
the engine do much braking for the whole train.
On Sun, 21 Jun 2026 15:08:37 -0400, Cryptoengineer
<petertrei@gmail.com> wrote:
<snippo>
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
To do this with regen, you'd have to put motors/generators on
every axle on every car, which is expensive and impractical.
I don't know enough to say if it would be practical to let
the engine do much braking for the whole train.
It'll become "practical" as soon as somebody finds a way to make money
from doing it. (I'm thinking here of the RR companies, not the people
selling them the equipment.)
Nuno Silva <nunojsilva@invalid.invalid> posted:
On 2026-06-21, Cryptoengineer wrote:
On 6/21/2026 5:16 AM, Ulf Kutzner wrote:[...]
Nuno Silva <nunojsilva@invalid.invalid> posted:
On 2026-06-21, Cryptoengineer wrote:
On 6/20/2026 2:50 PM, Scott Lurndal wrote:
There's also dynamic braking to consider, where the electricityEVs use regenerative braking, but dump the power back into the
generated by the traction motors while braking is dissipated as
well. The heat sinks (resistor grids) on those DE locos aren't small. >>>>>>
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's >>>>> experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art >>>>> on these?
Add bank of capacitors.
https://www.ijsat.org/papers/2025/2/3360.pdf
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
Note: it's applied air pressure that holds the brakes off, not the other
way around, that's what makes it fail-safe.
Depends on where you are with what kind of train. https://en.wikipedia.org/wiki/Vacuum_brake#Present-day_use_of_vacuum_brakes
Cryptoengineer <petertrei@gmail.com> posted:
On 6/21/2026 5:16 AM, Ulf Kutzner wrote:
Nuno Silva <nunojsilva@invalid.invalid> posted:
On 2026-06-21, Cryptoengineer wrote:
On 6/20/2026 2:50 PM, Scott Lurndal wrote:
kludge@panix.com (Scott Dorsey) writes:EVs use regenerative braking, but dump the power back into the
In article <3xyZR.6$Rg34.3@fx11.iad>, Scott Lurndal <slp53@pacbell.net> wrote:
Nuno Silva <nunojsilva@invalid.invalid> writes:
On 2026-06-20, Lawrence DrCOOliveiro wrote:Constant RPM. Electric power generated but not used for traction >>>>>>>> or auxiliary power needs is dissipated as heat.
On Fri, 19 Jun 2026 08:50:51 -0400 (EDT), Scott Dorsey wrote: >>>>>>>>>>
... like a diesel-electric locomotive.
I like diesel-electric locomotives. The diesel does what it does best
(run at a nearly constant speed), while the electrics do what they do
Do you mean the speed at which energy is generated or something else? >>>>>>>>
But that's not much loss because the engine doesn't take much fuel to >>>>>>> keep a constant speed when unloaded... as the load increases the fuel >>>>>>> demand goes up.
There's also dynamic braking to consider, where the electricity
generated by the traction motors while braking is dissipated as
well. The heat sinks (resistor grids) on those DE locos aren't small. >>>>>
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's >>>> experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art >>>> on these?
Add bank of capacitors.
https://www.ijsat.org/papers/2025/2/3360.pdf
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
To do this with regen, you'd have to put motors/generators on
every axle on every car, which is expensive and impractical.
I don't know enough to say if it would be practical to let
the engine do much braking for the whole train.
On freight trains, why not? Braking effort may more or less
be the same as traction effort.
If you need more braking, add air brakes or let your computer add them.
On 2026-06-21, Scott Dorsey wrote:
That would make sense but you need to
really trust your pantograph a lot because a small line dropout would mean >> a brief but total loss of braking.
I think such parameters are part of what must be tended to in railroad
design and maintenance. Pantograph placement relative to the contact
wire is not left to chance, and is supposed to be in a way that spreads
wear, for example.
A dropout could also be challenging for all the parts that don't run on >battery (at least traction motors and HVAC, possibly some of the
lighting), I guess. At least hopefully this won't be as potentially
damaging as leaving the circuit breaker(s) closed across AC phase
breaks?
A dropout could also be challenging for all the parts that don't run on >>battery (at least traction motors and HVAC, possibly some of the
lighting), I guess. At least hopefully this won't be as potentially >>damaging as leaving the circuit breaker(s) closed across AC phase
breaks?
I see dropouts now and then on the Northeast Corridor, usually for only a >second or so... lights go out and pitch of the engine changes but it comes >back pretty quickly. Most often just north of NYC. I guess I just view that >as a normal part of electric operation.
But trains need to be able to make emergency stops in a much shorter distance. So they need more stopping power than starting power.
According to Scott Dorsey <kludge@panix.com>:
A dropout could also be challenging for all the parts that don't run on >>>battery (at least traction motors and HVAC, possibly some of the >>>lighting), I guess. At least hopefully this won't be as potentially >>>damaging as leaving the circuit breaker(s) closed across AC phase
breaks?
I see dropouts now and then on the Northeast Corridor, usually for only a >>second or so... lights go out and pitch of the engine changes but it comes >>back pretty quickly. Most often just north of NYC. I guess I just view that
as a normal part of electric operation.
The Pennsylvania electrified at 25Hz, while the New Haven was converted from 25Hz to 60Hz in 1987 when Metro-North did system upgrades. The 60Hz section now
runs all the way to Boston. The two systems meet at Bowery Bay, between the Sunnyside Yard and the Hell Gate bridge, so that's probably the dropout you're
seeing.
The 25Hz section should be converted to 60Hz so they can get rid of the inverters and motor-generators that do the frequency conversion but I suspect Amtrak has higher priority capital needs.
On Mon, 22 Jun 2026 12:06:36 -0400, Cryptoengineer wrote:
But trains need to be able to make emergency stops in a much shorter
distance. So they need more stopping power than starting power.
But itrCOs never enough, is it? Road vehicles can abide by the rule that
you should not drive faster than you can stop in the portion of
available roadway visible to you. Trains cannot.
The 25Hz section should be converted to 60Hz so they can get rid of the
inverters and motor-generators that do the frequency conversion but I suspect
Amtrak has higher priority capital needs.
(Why was part of it electrified with 25 Hz? Was that in use for the
local power grid there?)
My question was going to be whether these "dropouts" are at random
places or consistently in the same place, although I was merely thinking
of AC phase breaks, not of moving between different electrification
systems.
(Why was part of it electrified with 25 Hz? Was that in use for the
local power grid there?)
In <111ciki$1t5pn$1@dont-email.me> Nuno Silva <nunojsilva@invalid.invalid> writes:
The 25Hz section should be converted to 60Hz so they can get rid of the
inverters and motor-generators that do the frequency conversion but I suspect
Amtrak has higher priority capital needs.
(Why was part of it electrified with 25 Hz? Was that in use for the
local power grid there?)
25 cycles per second was a MAJOR portion of the early
electrical grid, including the huge generators at (wait
for it...) Niagara Falls!
Robert Moses plant farther downstream. There is a similar size Sir Adam Beck station
on the Ontario side. I got there too late to go inside and take the elevator down to
see the ruins up close.
On Mon, 22 Jun 2026 12:06:36 -0400, Cryptoengineer wrote:
But trains need to be able to make emergency stops in a much shorter distance. So they need more stopping power than starting power.
But itrCOs never enough, is it? Road vehicles can abide by the rule that
you should not drive faster than you can stop in the portion of
available roadway visible to you. Trains cannot.
Nuno Silva <nunojsilva@invalid.invalid> wrote:
My question was going to be whether these "dropouts" are at random
places or consistently in the same place, although I was merely thinking
of AC phase breaks, not of moving between different electrification >systems.
I don't know. I don't remember them being consistent but I have not paid
the greatest of attention.
(Why was part of it electrified with 25 Hz? Was that in use for the
local power grid there?)
25 Hz is a win for high torque low speed AC motors, as well as for mechanical rectifiers, so a big portion of the plant at Niagara was
built for 25 Hz. 25 Hz mains were all over New York and Buffalo was
a huge center for electrolytic refining of aluminum (which takes a
lot of DC current, orignally from mechanical rectifiers). I think all
of that infrastructure was gone, along with the two-phase transmission system.
--scott
On 2026-06-21, Cryptoengineer wrote:
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's >experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art
on these?
On Sun, 21 Jun 2026 08:51:42 +0100, Nuno Silva
<nunojsilva@invalid.invalid> wrote:
On 2026-06-21, Cryptoengineer wrote:
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's >>experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art
on these?
Regenerative braking, as far as I know, always restores current to the source, whether batteried, overhead wires or conductor rails.
But rheostatic braking doesn't.
There doesn't seem to be any point in regen braking with
diesel-electric lcomotives, since they can't re-8se that power.
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
To do this with regen, you'd have to put motors/generators on--
every axle on every car, which is expensive and impractical.
I don't know enough to say if it would be practical to let
the engine do much braking for the whole train.
pt
On Sun, 21 Jun 2026 15:08:37 -0400, Cryptoengineer
<petertrei@gmail.com> wrote:
Mulling over it, I think part of the problem is that while trains
apply traction only at the engine(s), when they brake, braking is
applied on every car, via the pneumatic system where a vacuum
hold the brake shoes off the wheels (with the advantage that a
car that breaks free automatically brakes).
Trolley buses sometimes have regenerative braking. It is used when
going down hills to keep the bus from speeting up. In a diesel bus you
use a lower gear and use the engine compression. It stops the brake
shoes from overheating.
On Sun, 21 Jun 2026 08:51:42 +0100, Nuno Silva
<nunojsilva@invalid.invalid> wrote:
On 2026-06-21, Cryptoengineer wrote:
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's >experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art
on these?
Regenerative braking, as far as I know, always restores current to the source, whether batteried, overhead wires or conductor rails.
But rheostatic braking doesn't.
There doesn't seem to be any point in regen braking with
diesel-electric lcomotives, since they can't re-8se that power.
On 2026-06-22, Lawrence DrCOOliveiro wrote:
On Mon, 22 Jun 2026 12:06:36 -0400, Cryptoengineer wrote:
But trains need to be able to make emergency stops in a much shorter
distance. So they need more stopping power than starting power.
But itrCOs never enough, is it? Road vehicles can abide by the rule that
you should not drive faster than you can stop in the portion of
available roadway visible to you. Trains cannot.
Passenger trains may be able to pull that, the limiting factor might
become passenger safety, besides the design of the brakes (as the energy
has to go somewhere, it can't halt and catch fire).
Now freight trains have a much larger mass to stop, and that's even
without considering that in some places (at least the USA?) freight
trains are longer and may even double-deck containers.
It has to allow stronger braking, but there is going to be a
limit.
(What they're required to do, perhaps equivalent to the road vehicle >situation Lawrence mentioned, is to travel at a speed that allows them
to comply with the expected aspect of the following signal - so if a
freight train needs to decelerate quite early in order to be able to
stop before a signal at danger, then it has to do that, and the caution >aspect either forces a lower speed or indicates that the speed will have
to be reduced at the right moment (e.g. following EBICAB
indications). This may also define a ceiling for the top speed allowed, >depending on the distance between signals.)
For emergency braking, besides applying the full braking power, rail
vehicles will often also have sanders/sandboxes.
On 2026-06-23, Steve Hayes wrote:
On Sun, 21 Jun 2026 08:51:42 +0100, Nuno Silva
<nunojsilva@invalid.invalid> wrote:
On 2026-06-21, Cryptoengineer wrote:
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's >>>experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art >>>on these?
Regenerative braking, as far as I know, always restores current to the
source, whether batteried, overhead wires or conductor rails.
But rheostatic braking doesn't.
There doesn't seem to be any point in regen braking with
diesel-electric lcomotives, since they can't re-8se that power.
But they can, provided there *is* a battery for it?
Steve Hayes <hayesstw@telkomsa.net> posted:I remember capacitors. I last encountered them as a topic online when
On Sun, 21 Jun 2026 08:51:42 +0100, Nuno Silva
<nunojsilva@invalid.invalid> wrote:
On 2026-06-21, Cryptoengineer wrote:
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that what's
experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the art
on these?
Regenerative braking, as far as I know, always restores current to the
source, whether batteried, overhead wires or conductor rails.
But rheostatic braking doesn't.
There doesn't seem to be any point in regen braking with
diesel-electric lcomotives, since they can't re-8se that power.
Yes and not, see for capacitators in >https://en.wikipedia.org/wiki/Eurorunner#Technical
On Tue, 23 Jun 2026 09:00:51 GMT, Ulf Kutzner ><user2991@newsgrouper.org.invalid> wrote:
what's
Steve Hayes <hayesstw@telkomsa.net> posted:
On Sun, 21 Jun 2026 08:51:42 +0100, Nuno Silva
<nunojsilva@invalid.invalid> wrote:
=20
On 2026-06-21, Cryptoengineer wrote:
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that =
artexperimental is storing in a battery.
Might well be because of volume and weight, how is the state of the =
on these?=20
Regenerative braking, as far as I know, always restores current to the
source, whether batteried, overhead wires or conductor rails.
=20
But rheostatic braking doesn't.=20
=20
There doesn't seem to be any point in regen braking with
diesel-electric lcomotives, since they can't re-8se that power.
Yes and not, see for capacitators in >>https://en.wikipedia.org/wiki/Eurorunner#Technical
I remember capacitors. I last encountered them as a topic online when
I read that, to /really/ turn a computer off so it /really/ boots from >scratch, you need to leave it off for a minute or two for the
capacitors to discharge. Otherwise you may boot it into a prior state,
or into parts of a prior state.
Capacitor -- the other battery. As it were.
In a diesel bus you use a lower gear and use the engine compression.
It stops the brake shoes from overheating.
Paul S Person <psperson@old.netcom.invalid> writes:
On Tue, 23 Jun 2026 09:00:51 GMT, Ulf Kutzner ><user2991@newsgrouper.org.invalid> wrote:
Steve Hayes <hayesstw@telkomsa.net> posted:
On Sun, 21 Jun 2026 08:51:42 +0100, Nuno Silva
<nunojsilva@invalid.invalid> wrote:
=20
On 2026-06-21, Cryptoengineer wrote:=20
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that = >what's
experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the = >art
on these?
Regenerative braking, as far as I know, always restores current to the >>> source, whether batteried, overhead wires or conductor rails.
=20
But rheostatic braking doesn't.=20
=20
There doesn't seem to be any point in regen braking with
diesel-electric lcomotives, since they can't re-8se that power.
Yes and not, see for capacitators in >>https://en.wikipedia.org/wiki/Eurorunner#Technical
I remember capacitors. I last encountered them as a topic online when
I read that, to /really/ turn a computer off so it /really/ boots from >scratch, you need to leave it off for a minute or two for the
capacitors to discharge. Otherwise you may boot it into a prior state,
or into parts of a prior state.
For electrical safety when working on an electrical circuit, one
must work safely around (or manually discharge) large capacitors
in the power supply circuitry.
What you write about booting computers vis-a-vis capacitors is
completely incorrect.
Paul S Person <psperson@old.netcom.invalid> writes:So I've been told, and yet Ulf Kutzner provides an item (https://retrocomputing.stackexchange.com/questions/5642/was-there-ever-any-reason-to-wait-30-seconds-to-restart-a-c-1995-pc)
On Tue, 23 Jun 2026 09:00:51 GMT, Ulf Kutzner >><user2991@newsgrouper.org.invalid> wrote:
Steve Hayes <hayesstw@telkomsa.net> posted:
On Sun, 21 Jun 2026 08:51:42 +0100, Nuno Silva
<nunojsilva@invalid.invalid> wrote:
=20
On 2026-06-21, Cryptoengineer wrote:=20
EVs use regenerative braking, but dump the power back into the
batteries. This provides a great deal of extra range. You'd think
this would also be used in trains, but apparently its only used
in a few experimental units:
https://en.wikipedia.org/wiki/Hybrid_train
I think regenerative braking is in widespread use. I guess that = >>what's
experimental is storing in a battery.
Might well be because of volume and weight, how is the state of the = >>art
on these?
Regenerative braking, as far as I know, always restores current to the >>>> source, whether batteried, overhead wires or conductor rails.
=20
But rheostatic braking doesn't.=20
=20
There doesn't seem to be any point in regen braking with
diesel-electric lcomotives, since they can't re-8se that power.
Yes and not, see for capacitators in >>>https://en.wikipedia.org/wiki/Eurorunner#Technical
I remember capacitors. I last encountered them as a topic online when
I read that, to /really/ turn a computer off so it /really/ boots from >>scratch, you need to leave it off for a minute or two for the
capacitors to discharge. Otherwise you may boot it into a prior state,
or into parts of a prior state.
For electrical safety when working on an electrical circuit, one
must work safely around (or manually discharge) large capacitors
in the power supply circuitry.
What you write about booting computers vis-a-vis capacitors is
completely incorrect.
In <111ciki$1t5pn$1@dont-email.me> Nuno Silva <nunojsilva@invalid.invalid> writes:
25 cycles per second was a MAJOR portion of the early
electrical grid, including the huge generators at (wait
for it...) Niagara Falls!
[stuff deleted]
25 cycles per second was a MAJOR portion of the early"Niagara Falls! Slowly I turned, step by step, inch by inch... I took my >revenge!".
electrical grid, including the huge generators at (wait
for it...) Niagara Falls!
On 6/22/26 17:24, danny burstein wrote:
In <111ciki$1t5pn$1@dont-email.me> Nuno Silva
<nunojsilva@invalid.invalid> writes:
[stuff deleted]
25 cycles per second was a MAJOR portion of the early"Niagara Falls! Slowly I turned, step by step, inch by inch... I took my revenge!".
electrical grid, including the huge generators at (wait
for it...) Niagara Falls!
[stuff deleted]
[stuff deleted]
25 cycles per second was a MAJOR portion of the early"Niagara Falls! Slowly I turned, step by step, inch by inch... I took my >>revenge!".
electrical grid, including the huge generators at (wait
for it...) Niagara Falls!
amusingly enough 1975ish, I was in the IND (8th Ave) subway station
attached to that horrible facility called (what's left of) Penn Station.
This was middle of winter, with a weeklong sub zero Farenheit cold wave.
I have no idea how and why, but part of the incandescent platform
lighting was tied into the 25 hz rail circuitry. The reason I
know this is... the lamps were flickering at a just barely detectable
fifty flashes/second...
On 6/22/26 17:24, danny burstein wrote:https://www.youtube.com/watch?v=Dh2yk23SkCw for those that are curious.
In <111ciki$1t5pn$1@dont-email.me> Nuno Silva
<nunojsilva@invalid.invalid> writes:
[stuff deleted]
25 cycles per second was a MAJOR portion of the early"Niagara Falls! Slowly I turned, step by step, inch by inch... I took my
electrical grid, including the huge generators at (wait
for it...) Niagara Falls!
revenge!".
[stuff deleted]
The guys in the band behind them seemed to be enjoying it.
What you write about booting computers vis-a-vis capacitors is
completely incorrect.
Maybe a minute or two is too much but still
(applies to today's TV sets, too): >https://retrocomputing.stackexchange.com/questions/5642/was-there-ever-any-reason-to-wait-30-seconds-to-restart-a-c-1995-pc
[stuff deleted]
25 cycles per second was a MAJOR portion of the early"Niagara Falls! Slowly I turned, step by step, inch by inch... I took my
electrical grid, including the huge generators at (wait
for it...) Niagara Falls!
revenge!".
amusingly enough 1975ish, I was in the IND (8th Ave) subway station
attached to that horrible facility called (what's left of) Penn Station.
This was middle of winter, with a weeklong sub zero Farenheit cold wave.
I have no idea how and why, but part of the incandescent platform
lighting was tied into the 25 hz rail circuitry. The reason I
know this is... the lamps were flickering at a just barely detectable
fifty flashes/second...
On 6/25/26 10:37, BCFD 36 wrote:
On 6/22/26 17:24, danny burstein wrote:https://www.youtube.com/watch?v=Dh2yk23SkCw for those that are curious.
In <111ciki$1t5pn$1@dont-email.me> Nuno Silva
<nunojsilva@invalid.invalid> writes:
[stuff deleted]
25 cycles per second was a MAJOR portion of the early"Niagara Falls! Slowly I turned, step by step, inch by inch... I took
electrical grid, including the huge generators at (wait
for it...) Niagara Falls!
my revenge!".
[stuff deleted]
The guys in the band behind them seemed to be enjoying it.
I've read that the NYC subway uses about as much power as the entire
state of Vermont. Haven't confirmed this, but it seems plausible.
I've read that the NYC subway uses about as much power as the entire
state of Vermont. Haven't confirmed this, but it seems plausible.
Cryptoengineer <petertrei@gmail.com> wrote:
I've read that the NYC subway uses about as much power as the entire
state of Vermont. Haven't confirmed this, but it seems plausible.
They have electricity in Vermont now? Wow!
Cryptoengineer <petertrei@gmail.com> wrote:
I've read that the NYC subway uses about as much power as the entire
state of Vermont. Haven't confirmed this, but it seems plausible.
They have electricity in Vermont now? Wow!
--scott
On 6/26/26 13:26, Scott Dorsey wrote:
Cryptoengineer <petertrei@gmail.com> wrote:
I've read that the NYC subway uses about as much power as the entire
state of Vermont. Haven't confirmed this, but it seems plausible.
They have electricity in Vermont now? Wow!
--scott
Yeps the whole nation is going to hell in a hand-basket.
Private refrigeration has destroyed the Ice business.
And the cost of a buggy-whip has gone thru the roof now
that only the billionaires can afford a stable.
Indoor plumbing won't build the character that one develops
running to the outhouse in midwinter thru the snow.
Well you folks will continue to go down the drain with all
the technological toys you use...
On 2026-06-27, BobbieSellers wrote:
On 6/26/26 13:26, Scott Dorsey wrote:
Cryptoengineer <petertrei@gmail.com> wrote:
I've read that the NYC subway uses about as much power as the entire
state of Vermont. Haven't confirmed this, but it seems plausible.
They have electricity in Vermont now? Wow!
--scott
Yeps the whole nation is going to hell in a hand-basket.
Private refrigeration has destroyed the Ice business.
And the cost of a buggy-whip has gone thru the roof now
that only the billionaires can afford a stable.
Indoor plumbing won't build the character that one develops
running to the outhouse in midwinter thru the snow.
Well you folks will continue to go down the drain with all
the technological toys you use...
Yeah, and there's this thing where vehicles can have much higher
capacity and run efficiently on electrical power with no need for large batteries, and even run at high speeds without need to employ tires -
that's going to destroy the US EV business. And the oil lobby will go
haywire too.
On 6/27/26 01:38, Nuno Silva wrote:
On 2026-06-27, BobbieSellers wrote:-a-a-a-a-a-a-a-a-a Yes but our near ancestors got by with coal-burning steam
On 6/26/26 13:26, Scott Dorsey wrote:
Cryptoengineer-a <petertrei@gmail.com> wrote:
I've read that the NYC subway uses about as much power as the entire >>>>> state of Vermont. Haven't confirmed this, but it seems plausible.
They have electricity in Vermont now?-a Wow!
--scott
-a-a-a-aYeps the whole nation is going to hell in a hand-basket.
-a-a-a-aPrivate refrigeration has destroyed the Ice business.
-a-a-a-aAnd the cost of a buggy-whip has gone thru the roof now
that only the billionaires can afford a stable.
-a-a-a-aIndoor plumbing won't build the character that one develops
running to the outhouse in midwinter thru the snow.
-a-a-a-aWell you folks will continue to go down the drain with all
the technological toys you use...
Yeah, and there's this thing where vehicles can have much higher
capacity and run efficiently on electrical power with no need for large
batteries, and even run at high speeds without need to employ tires -
that's going to destroy the US EV business. And the oil lobby will go
haywire too.
locomotives, bicycles and horse motivated carriages and wagons.
-a-a-a-aThat coal smoke and horse droppings flavored the air of big
towns and cities. You knew where you were by the smell of the air.
-a-a-a-aWhy do you think so many went West to settle the praires.
-a-a-a-aBut what distinguished San Francisco from the 1950s thru the
1970s were the coffee roasting houses by the water front. You knew
you were in town when that odor rose to meet you coming off the
Bay Bridge. Horse dust was further back in time when the city had
to employ sweepers to keep the streets less odorous.-a We used to
have bakeries that emitted a yeasty alcoholic odor and probablu
the big breweries did as well.
-a-a-a-aBut what distinguished San Francisco from the 1950s thru the
1970s were the coffee roasting houses by the water front. You knew
you were in town when that odor rose to meet you coming off the
Bay Bridge. Horse dust was further back in time when the city had
to employ sweepers to keep the streets less odorous.-a We used to
have bakeries that emitted a yeasty alcoholic odor and probablu
the big breweries did as well.
I can remember when Mass Ave near MIT smelled of chocolate, from
the Necco Wafer factory nearby.
1970s were the coffee roasting houses by the water front. You knew
you were in town when that odor rose to meet you coming off the
Bay Bridge. Horse dust was further back in time when the city had
to employ sweepers to keep the streets less odorous.-a We used to
have bakeries that emitted a yeasty alcoholic odor and probablu
the big breweries did as well.
I can remember when Mass Ave near MIT smelled of chocolate, from
the Necco Wafer factory nearby.
The chocolate smell from the Junior Mints factory across the street
was a lot stronger when I was working there 40 years ago.
In <111mn9b$q93$1@panix2.panix.com> kludge@panix.com (Scott Dorsey) writes:
Cryptoengineer <petertrei@gmail.com> wrote:
I've read that the NYC subway uses about as much power as the entire >>>state of Vermont. Haven't confirmed this, but it seems plausible.
They have electricity in Vermont now? Wow!
just during thunderstorms..
On Fri, 26 Jun 2026 20:28:29 -0000 (UTC), danny burstein
<dannyb@panix.com> wrote:
In <111mn9b$q93$1@panix2.panix.com> kludge@panix.com (Scott Dorsey) writes: >>
Cryptoengineer <petertrei@gmail.com> wrote:
I've read that the NYC subway uses about as much power as the entire
state of Vermont. Haven't confirmed this, but it seems plausible.
They have electricity in Vermont now? Wow!
just during thunderstorms..
I dunno - it's amazing what you can do with gerbils on treadmills to
run generators...
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