Does anyone know the fancy/technical name for a model railway track cleaner
that's based on flyback pulses from a blocking oscillator to break down
oxide and crud on the rails?

Googling "model railway+track cleaner" produced a few examples of commercial
units but none were referred to by the technical name, I need some schematic
examples to base a similar gadget to clean switch contacts in a 12V system
that occasionally get corroded.

TIA.

"ian field" wrote in message
...
Does anyone know the fancy/technical name for a model railway track
cleaner that's based on flyback pulses from a blocking oscillator to break
down oxide and crud on the rails?

Googling "model railway+track cleaner" produced a few examples of
commercial units but none were referred to by the technical name, I need
some schematic examples to base a similar gadget to clean switch contacts
in a 12V system that occasionally get corroded.

TIA.


Will this help you?
http://freespace.virgin.net/c.gardner/semg/relco.htm

also http://www.merg.org.uk/resources/faq.htm
Track cleaner A device for cleaning track so that dirt or other
deposits do not impede the flow of electric current. A number of methods
exist to accomplish this. MERG Technical Bulletin A4/1 features the Relco
Track Cleaner which superimposes a high frequency, high voltage signal over
the traction current. This burns through track deposits when traction is
interrupted. Mechanical abrasive rubber-type products are also available
such as the Peco PL41 Rail Cleaner and the MERG kit 83, PCB and Track
Cleaner. These must be rubbed over the track to clean it. A variety of
solvents applied with a clean cloth are also suitable as are a number of
wagon-mounted abrasive blocks. A popular MERG method is to polish the rail
tops with the rough surface of common hardboard.
July 2006

"Oppie" wrote in message
.. .

"ian field" wrote in message
...
Does anyone know the fancy/technical name for a model railway track
cleaner that's based on flyback pulses from a blocking oscillator to
break down oxide and crud on the rails?

Googling "model railway+track cleaner" produced a few examples of
commercial units but none were referred to by the technical name, I need
some schematic examples to base a similar gadget to clean switch contacts
in a 12V system that occasionally get corroded.

TIA.


Will this help you?
http://freespace.virgin.net/c.gardner/semg/relco.htm

also http://www.merg.org.uk/resources/faq.htm
Track cleaner A device for cleaning track so that dirt or other
deposits do not impede the flow of electric current. A number of methods
exist to accomplish this. MERG Technical Bulletin A4/1 features the Relco
Track Cleaner which superimposes a high frequency, high voltage signal
over the traction current. This burns through track deposits when traction
is interrupted. Mechanical abrasive rubber-type products are also
available such as the Peco PL41 Rail Cleaner and the MERG kit 83, PCB and
Track Cleaner. These must be rubbed over the track to clean it. A variety
of solvents applied with a clean cloth are also suitable as are a number
of wagon-mounted abrasive blocks. A popular MERG method is to polish the
rail tops with the rough surface of common hardboard.
July 2006



That's one of the pages I found googling and it doesn't mention the
technical name for an electronic track cleaner - I'll have to phone the
local model shop and ask them.

"ian field" wrote in message
news

"Oppie" wrote in message
.. .

"ian field" wrote in message
...
Does anyone know the fancy/technical name for a model railway track
cleaner that's based on flyback pulses from a blocking oscillator to
break down oxide and crud on the rails?

Googling "model railway+track cleaner" produced a few examples of
commercial units but none were referred to by the technical name, I need
some schematic examples to base a similar gadget to clean switch
contacts in a 12V system that occasionally get corroded.

TIA.


Will this help you?
http://freespace.virgin.net/c.gardner/semg/relco.htm

also http://www.merg.org.uk/resources/faq.htm
Track cleaner A device for cleaning track so that dirt or other
deposits do not impede the flow of electric current. A number of methods
exist to accomplish this. MERG Technical Bulletin A4/1 features the Relco
Track Cleaner which superimposes a high frequency, high voltage signal
over the traction current. This burns through track deposits when
traction is interrupted. Mechanical abrasive rubber-type products are
also available such as the Peco PL41 Rail Cleaner and the MERG kit 83,
PCB and Track Cleaner. These must be rubbed over the track to clean it. A
variety of solvents applied with a clean cloth are also suitable as are a
number of wagon-mounted abrasive blocks. A popular MERG method is to
polish the rail tops with the rough surface of common hardboard.
July 2006



That's one of the pages I found googling and it doesn't mention the
technical name for an electronic track cleaner - I'll have to phone the
local model shop and ask them.

From what I can make of it, the device monitors the load and when it drops
out, superimposes HF pulses on top of the DC feed. Sounds similar to the arc
lamp ignitors I work with - a 20 turn winding in series with the DC feed to
the lamp (track) and a 2 turn primary fed by a spark gap connected to a
600V charged capacitor. Spark gap breaks over and dumps capacitor into
primary. Nice sparks on the secondary!
Can't imagine this is too kind to any electronics installed in the layout
but then again, probably doesn't need the 14kv that my lamps need.
Happy Hunting
Oppie

"Oppie" wrote in message
.. .

"ian field" wrote in message
news

"Oppie" wrote in message
.. .

"ian field" wrote in message
...
Does anyone know the fancy/technical name for a model railway track
cleaner that's based on flyback pulses from a blocking oscillator to
break down oxide and crud on the rails?

Googling "model railway+track cleaner" produced a few examples of
commercial units but none were referred to by the technical name, I
need some schematic examples to base a similar gadget to clean switch
contacts in a 12V system that occasionally get corroded.

TIA.


Will this help you?
http://freespace.virgin.net/c.gardner/semg/relco.htm

also http://www.merg.org.uk/resources/faq.htm
Track cleaner A device for cleaning track so that dirt or other
deposits do not impede the flow of electric current. A number of methods
exist to accomplish this. MERG Technical Bulletin A4/1 features the
Relco Track Cleaner which superimposes a high frequency, high voltage
signal over the traction current. This burns through track deposits when
traction is interrupted. Mechanical abrasive rubber-type products are
also available such as the Peco PL41 Rail Cleaner and the MERG kit 83,
PCB and Track Cleaner. These must be rubbed over the track to clean it.
A variety of solvents applied with a clean cloth are also suitable as
are a number of wagon-mounted abrasive blocks. A popular MERG method is
to polish the rail tops with the rough surface of common hardboard.
July 2006



That's one of the pages I found googling and it doesn't mention the
technical name for an electronic track cleaner - I'll have to phone the
local model shop and ask them.

From what I can make of it, the device monitors the load and when it drops
out, superimposes HF pulses on top of the DC feed. Sounds similar to the
arc lamp ignitors I work with - a 20 turn winding in series with the DC
feed to the lamp (track) and a 2 turn primary fed by a spark gap
connected to a 600V charged capacitor. Spark gap breaks over and dumps
capacitor into primary. Nice sparks on the secondary!
Can't imagine this is too kind to any electronics installed in the layout
but then again, probably doesn't need the 14kv that my lamps need.
Happy Hunting
Oppie


That's more or less right, its based on a blocking oscillator with a winding
in series with the feed to the track. In a properly designed unit normal
current flow to the track causes the BO to stall and draw minimal current,
as soon as crud on the track breaks the circuit the BO starts and the high
voltage pulses burn the crud off.

A google search for "model train+track cleaner" didn't reveal the technical
name for the unit and I've phoned all the model shops in the local
directory, I've seen a circuit in one of the electronics magazines referred
to by the technical mane, but there's a lot of magazines to search through.

Oppie wrote:

"ian field" wrote in message
news
"Oppie" wrote in message
...

"ian field" wrote in message
...

Does anyone know the fancy/technical name for a model railway track
cleaner that's based on flyback pulses from a blocking oscillator to
break down oxide and crud on the rails?

Googling "model railway+track cleaner" produced a few examples of
commercial units but none were referred to by the technical name, I need
some schematic examples to base a similar gadget to clean switch
contacts in a 12V system that occasionally get corroded.

TIA.


Will this help you?
http://freespace.virgin.net/c.gardner/semg/relco.htm

also http://www.merg.org.uk/resources/faq.htm
Track cleaner A device for cleaning track so that dirt or other
deposits do not impede the flow of electric current. A number of methods
exist to accomplish this. MERG Technical Bulletin A4/1 features the Relco
Track Cleaner which superimposes a high frequency, high voltage signal
over the traction current. This burns through track deposits when
traction is interrupted. Mechanical abrasive rubber-type products are
also available such as the Peco PL41 Rail Cleaner and the MERG kit 83,
PCB and Track Cleaner. These must be rubbed over the track to clean it. A
variety of solvents applied with a clean cloth are also suitable as are a
number of wagon-mounted abrasive blocks. A popular MERG method is to
polish the rail tops with the rough surface of common hardboard.
July 2006



That's one of the pages I found googling and it doesn't mention the
technical name for an electronic track cleaner - I'll have to phone the
local model shop and ask them.


From what I can make of it, the device monitors the load and when it drops
out, superimposes HF pulses on top of the DC feed. Sounds similar to the arc
lamp ignitors I work with - a 20 turn winding in series with the DC feed to
the lamp (track) and a 2 turn primary fed by a spark gap connected to a
600V charged capacitor. Spark gap breaks over and dumps capacitor into
primary. Nice sparks on the secondary!
Can't imagine this is too kind to any electronics installed in the layout
but then again, probably doesn't need the 14kv that my lamps need.


When I was a kid I built myself something similar for a Fleischmann
model railroad. Those are DC operated. I don't have the circuitry or
schematic anymore but basically I ran the pulses all the time. They got
shorted out as long as the locomotive made contact and the spike voltage
only ran up when dirt got in between.

I built a simple pulse generator with Ge transistors (and blew quite a
few in the process), a few Hertz, then hung a reversed transformer from
an old tube radio in series with the variable transformer output. Since
I had also built the regulator myself it compensated for the DC drop
across the added transformer winding. Well, to some extent because I had
no clue about loop stability and all that back then. Guess I lucked out.
Of course, at that age I was blissfully unaware of EMC and all that
stuff. So don't do this at home ;-)

--
Regards, Joerg

http://www.analogconsultants.com

Oppie wrote:

"ian field" wrote in message
news
"Oppie" wrote in message
...

"ian field" wrote in message
...

Does anyone know the fancy/technical name for a model railway track
cleaner that's based on flyback pulses from a blocking oscillator to
break down oxide and crud on the rails?

Googling "model railway+track cleaner" produced a few examples of
commercial units but none were referred to by the technical name, I need
some schematic examples to base a similar gadget to clean switch
contacts in a 12V system that occasionally get corroded.

TIA.


Will this help you?
http://freespace.virgin.net/c.gardner/semg/relco.htm

also http://www.merg.org.uk/resources/faq.htm
Track cleaner A device for cleaning track so that dirt or other
deposits do not impede the flow of electric current. A number of methods
exist to accomplish this. MERG Technical Bulletin A4/1 features the Relco
Track Cleaner which superimposes a high frequency, high voltage signal
over the traction current. This burns through track deposits when
traction is interrupted. Mechanical abrasive rubber-type products are
also available such as the Peco PL41 Rail Cleaner and the MERG kit 83,
PCB and Track Cleaner. These must be rubbed over the track to clean it. A
variety of solvents applied with a clean cloth are also suitable as are a
number of wagon-mounted abrasive blocks. A popular MERG method is to
polish the rail tops with the rough surface of common hardboard.
July 2006



That's one of the pages I found googling and it doesn't mention the
technical name for an electronic track cleaner - I'll have to phone the
local model shop and ask them.


From what I can make of it, the device monitors the load and when it drops
out, superimposes HF pulses on top of the DC feed. Sounds similar to the arc
lamp ignitors I work with - a 20 turn winding in series with the DC feed to
the lamp (track) and a 2 turn primary fed by a spark gap connected to a
600V charged capacitor. Spark gap breaks over and dumps capacitor into
primary. Nice sparks on the secondary!
Can't imagine this is too kind to any electronics installed in the layout
but then again, probably doesn't need the 14kv that my lamps need.


When I was a kid I built myself something similar for a Fleischmann
model railroad. Those are DC operated. I don't have the circuitry or
schematic anymore but basically I ran the pulses all the time. They got
shorted out as long as the locomotive made contact and the spike voltage
only ran up when dirt got in between.

I built a simple pulse generator with Ge transistors (and blew quite a
few in the process), a few Hertz, then hung a reversed transformer from
an old tube radio in series with the variable transformer output. Since
I had also built the regulator myself it compensated for the DC drop
across the added transformer winding. Well, to some extent because I had
no clue about loop stability and all that back then. Guess I lucked out.
Of course, at that age I was blissfully unaware of EMC and all that
stuff. So don't do this at home ;-)

--
Regards, Joerg

http://www.analogconsultants.com

"Joerg" wrote in message
...
Oppie wrote:

"ian field" wrote in message
news
"Oppie" wrote in message
m...

"ian field" wrote in message
...

Does anyone know the fancy/technical name for a model railway track
cleaner that's based on flyback pulses from a blocking oscillator to
break down oxide and crud on the rails?

Googling "model railway+track cleaner" produced a few examples of
commercial units but none were referred to by the technical name, I
need some schematic examples to base a similar gadget to clean switch
contacts in a 12V system that occasionally get corroded.

TIA.


Will this help you?
http://freespace.virgin.net/c.gardner/semg/relco.htm

also http://www.merg.org.uk/resources/faq.htm
Track cleaner A device for cleaning track so that dirt or other
deposits do not impede the flow of electric current. A number of
methods exist to accomplish this. MERG Technical Bulletin A4/1 features
the Relco Track Cleaner which superimposes a high frequency, high
voltage signal over the traction current. This burns through track
deposits when traction is interrupted. Mechanical abrasive rubber-type
products are also available such as the Peco PL41 Rail Cleaner and the
MERG kit 83, PCB and Track Cleaner. These must be rubbed over the track
to clean it. A variety of solvents applied with a clean cloth are also
suitable as are a number of wagon-mounted abrasive blocks. A popular
MERG method is to polish the rail tops with the rough surface of common
hardboard.
July 2006



That's one of the pages I found googling and it doesn't mention the
technical name for an electronic track cleaner - I'll have to phone the
local model shop and ask them.


From what I can make of it, the device monitors the load and when it
drops out, superimposes HF pulses on top of the DC feed. Sounds similar
to the arc lamp ignitors I work with - a 20 turn winding in series with
the DC feed to the lamp (track) and a 2 turn primary fed by a spark gap
connected to a 600V charged capacitor. Spark gap breaks over and dumps
capacitor into primary. Nice sparks on the secondary!
Can't imagine this is too kind to any electronics installed in the layout
but then again, probably doesn't need the 14kv that my lamps need.


When I was a kid I built myself something similar for a Fleischmann model
railroad. Those are DC operated. I don't have the circuitry or schematic
anymore but basically I ran the pulses all the time. They got shorted out
as long as the locomotive made contact and the spike voltage only ran up
when dirt got in between.

I built a simple pulse generator with Ge transistors (and blew quite a few
in the process), a few Hertz, then hung a reversed transformer from an old
tube radio in series with the variable transformer output.


Didn't the resistance of the transformer's primary drop most of your
available suply voltage when the train was drawing (tried to draw) traction
current?

Chris



Since
I had also built the regulator myself it compensated for the DC drop
across the added transformer winding. Well, to some extent because I had
no clue about loop stability and all that back then. Guess I lucked out.
Of course, at that age I was blissfully unaware of EMC and all that stuff.
So don't do this at home ;-)

--
Regards, Joerg

http://www.analogconsultants.com

christofire wrote:

"Joerg" wrote in message
...

Oppie wrote:


"ian field" wrote in message
news

"Oppie" wrote in message
om...


"ian field" wrote in message
...


Does anyone know the fancy/technical name for a model railway track
cleaner that's based on flyback pulses from a blocking oscillator to
break down oxide and crud on the rails?

Googling "model railway+track cleaner" produced a few examples of
commercial units but none were referred to by the technical name, I
need some schematic examples to base a similar gadget to clean switch
contacts in a 12V system that occasionally get corroded.

TIA.


Will this help you?
http://freespace.virgin.net/c.gardner/semg/relco.htm

also http://www.merg.org.uk/resources/faq.htm
Track cleaner A device for cleaning track so that dirt or other
deposits do not impede the flow of electric current. A number of
methods exist to accomplish this. MERG Technical Bulletin A4/1 features
the Relco Track Cleaner which superimposes a high frequency, high
voltage signal over the traction current. This burns through track
deposits when traction is interrupted. Mechanical abrasive rubber-type
products are also available such as the Peco PL41 Rail Cleaner and the
MERG kit 83, PCB and Track Cleaner. These must be rubbed over the track
to clean it. A variety of solvents applied with a clean cloth are also
suitable as are a number of wagon-mounted abrasive blocks. A popular
MERG method is to polish the rail tops with the rough surface of common
hardboard.
July 2006



That's one of the pages I found googling and it doesn't mention the
technical name for an electronic track cleaner - I'll have to phone the
local model shop and ask them.


From what I can make of it, the device monitors the load and when it
drops out, superimposes HF pulses on top of the DC feed. Sounds similar
to the arc lamp ignitors I work with - a 20 turn winding in series with
the DC feed to the lamp (track) and a 2 turn primary fed by a spark gap
connected to a 600V charged capacitor. Spark gap breaks over and dumps
capacitor into primary. Nice sparks on the secondary!
Can't imagine this is too kind to any electronics installed in the layout
but then again, probably doesn't need the 14kv that my lamps need.


When I was a kid I built myself something similar for a Fleischmann model
railroad. Those are DC operated. I don't have the circuitry or schematic
anymore but basically I ran the pulses all the time. They got shorted out
as long as the locomotive made contact and the spike voltage only ran up
when dirt got in between.

I built a simple pulse generator with Ge transistors (and blew quite a few
in the process), a few Hertz, then hung a reversed transformer from an old
tube radio in series with the variable transformer output.



Didn't the resistance of the transformer's primary drop most of your
available suply voltage when the train was drawing (tried to draw) traction
current?


Well, sure, but read on.


Since

I had also built the regulator myself it compensated for the DC drop
across the added transformer winding. Well, to some extent because I had
no clue about loop stability and all that back then. Guess I lucked out.
Of course, at that age I was blissfully unaware of EMC and all that stuff.
So don't do this at home ;-)


I was just a highschool kid so most of the time I scavenged schematics
from books in the library and combined things I found. There, they had a
nice book about railroad electronics with an electronically stabilized
"Fahrstromtransformator", that's the usual rheostat-type transformer you
could buy in those days and they had not electronics back then. Now, I
looked at the circuit and gasp placed the pulse transformer winding
between the emitters of the pass transistors and where the feedback loop
taps off. No reverse Vbe diode, nothing. In fact I didn't even know what
reverse Vbe is. I consider it a miracle that the whole thing never went
unstable and smoked out the motor of the rather expensive locomotive I
had on the track. I am also still baffled by the fact that it didn't
melt down the base-emitter junctions.

Then I caused a really stupid blunder: The old Fleischmann transformer
had a fixed voltage output for street lamps and such. Running that big
green thing next to my new sleek electronic version wouldn't look good.
I always created fancy enclosures, blending in with the surroundings.
So, looking at the schematic, tada! I figured I could just tap the
secondary and that'll be it. Drilled a couple holes, mounted cable posts
so it'll look neat and professional. It didn't occur to me that it had a
much higher voltage because of the regulator overhead and ... flash -
POOF. At least $20 worth of bulbs, gone. This was in early-70's Dollars,
very painful.

--
Regards, Joerg

http://www.analogconsultants.com

"Joerg" wrote in message
et...
christofire wrote:

"Joerg" wrote in message
...

Oppie wrote:


"ian field" wrote in message
news

"Oppie" wrote in message
. com...


"ian field" wrote in message
...


Does anyone know the fancy/technical name for a model railway track
cleaner that's based on flyback pulses from a blocking oscillator to
break down oxide and crud on the rails?

Googling "model railway+track cleaner" produced a few examples of
commercial units but none were referred to by the technical name, I
need some schematic examples to base a similar gadget to clean switch
contacts in a 12V system that occasionally get corroded.

TIA.


Will this help you?
http://freespace.virgin.net/c.gardner/semg/relco.htm

also http://www.merg.org.uk/resources/faq.htm
Track cleaner A device for cleaning track so that dirt or other
deposits do not impede the flow of electric current. A number of
methods exist to accomplish this. MERG Technical Bulletin A4/1
features the Relco Track Cleaner which superimposes a high frequency,
high voltage signal over the traction current. This burns through
track deposits when traction is interrupted. Mechanical abrasive
rubber-type products are also available such as the Peco PL41 Rail
Cleaner and the MERG kit 83, PCB and Track Cleaner. These must be
rubbed over the track to clean it. A variety of solvents applied with
a clean cloth are also suitable as are a number of wagon-mounted
abrasive blocks. A popular MERG method is to polish the rail tops
with the rough surface of common hardboard.
July 2006



That's one of the pages I found googling and it doesn't mention the
technical name for an electronic track cleaner - I'll have to phone the
local model shop and ask them.


From what I can make of it, the device monitors the load and when it
drops out, superimposes HF pulses on top of the DC feed. Sounds similar
to the arc lamp ignitors I work with - a 20 turn winding in series with
the DC feed to the lamp (track) and a 2 turn primary fed by a spark gap
connected to a 600V charged capacitor. Spark gap breaks over and dumps
capacitor into primary. Nice sparks on the secondary!
Can't imagine this is too kind to any electronics installed in the
layout but then again, probably doesn't need the 14kv that my lamps
need.


When I was a kid I built myself something similar for a Fleischmann model
railroad. Those are DC operated. I don't have the circuitry or schematic
anymore but basically I ran the pulses all the time. They got shorted out
as long as the locomotive made contact and the spike voltage only ran up
when dirt got in between.

I built a simple pulse generator with Ge transistors (and blew quite a
few in the process), a few Hertz, then hung a reversed transformer from
an old tube radio in series with the variable transformer output.



Didn't the resistance of the transformer's primary drop most of your
available suply voltage when the train was drawing (tried to draw)
traction current?


Well, sure, but read on.


Since

I had also built the regulator myself it compensated for the DC drop
across the added transformer winding. Well, to some extent because I had
no clue about loop stability and all that back then. Guess I lucked out.
Of course, at that age I was blissfully unaware of EMC and all that
stuff. So don't do this at home ;-)


I was just a highschool kid so most of the time I scavenged schematics
from books in the library and combined things I found. There, they had a
nice book about railroad electronics with an electronically stabilized
"Fahrstromtransformator", that's the usual rheostat-type transformer you
could buy in those days and they had not electronics back then. Now, I
looked at the circuit and gasp placed the pulse transformer winding
between the emitters of the pass transistors and where the feedback loop
taps off. No reverse Vbe diode, nothing. In fact I didn't even know what
reverse Vbe is. I consider it a miracle that the whole thing never went
unstable and smoked out the motor of the rather expensive locomotive I had
on the track. I am also still baffled by the fact that it didn't melt down
the base-emitter junctions.

Then I caused a really stupid blunder: The old Fleischmann transformer had
a fixed voltage output for street lamps and such. Running that big green
thing next to my new sleek electronic version wouldn't look good. I always
created fancy enclosures, blending in with the surroundings. So, looking
at the schematic, tada! I figured I could just tap the secondary and
that'll be it. Drilled a couple holes, mounted cable posts so it'll look
neat and professional. It didn't occur to me that it had a much higher
voltage because of the regulator overhead and ... flash - POOF. At least
$20 worth of bulbs, gone. This was in early-70's Dollars, very painful.

--
Regards, Joerg

http://www.analogconsultants.com

If I wanted it for model railway use, one of the first things I'd try to get
away with is a couple of capacitors on one side of the rectifier to make it
a voltage doubler - not sufficient capacitance to significantly increase
traction current but enough to double the peak voltage when crud insulates
the wheels from the track, say about 0.22uF mylars. The rheostat was usually
a simple variable resistor (not a potential divider) so the doubled peak
voltage would be applied when contact was lost, at any rheostat setting.

ian field wrote:

If I wanted it for model railway use, one of the first things I'd try to get
away with is a couple of capacitors on one side of the rectifier to make it
a voltage doubler - not sufficient capacitance to significantly increase
traction current but enough to double the peak voltage when crud insulates
the wheels from the track, say about 0.22uF mylars. The rheostat was usually
a simple variable resistor (not a potential divider) so the doubled peak
voltage would be applied when contact was lost, at any rheostat setting.


Why don't you learn to trim what you're replying to?


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida