# Capacitor Question From an Electrical Idiot



## Murv2 (Nov 5, 2017)

I have a lot of really old engines that stall on my switch frogs because the wheelbase of the pickups is too narrow. Will a capacitor solve this problem? I googled it and found a recommendation for Tantulum 25V 100uF but they very quickly ended up too deep in the weeds for someone who doesn't understand electricity beyond 'flip the switch and it works'. My engines are old roundhouse, bowser, mantua and tyco kits and AHM diesels.


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## Dennis461 (Jan 5, 2018)

Capacitor to do the job would be as large as the locomotive.


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## LateStarter (Mar 12, 2016)

Check this out...





KeepAlive ® | TrainControlSystems







tcsdcc.com





To give you an idea of how they fit, I have one in a Bachman 44ton.
There's also lots of info, and a few YouTube vids out there.


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## Murv2 (Nov 5, 2017)

Do those work with DC? I'm interested, think I could stick one in the tender...


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## wvgca (Jan 21, 2013)

in DC you need twice the amount of caps, and it really doesn't like to work at low speeds [and low voltages], where it is needed most ... so not really, nope ...
i did a test loco some years back, and it didn't work well .. DC momentum worked better, but not loco based .. sorry ..


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## Lemonhawk (Sep 24, 2013)

Note that "Keep alives" work with DCC, not DC. A capacitor on a DC locomotive will not work well. First the capacitor wound need to Non Polarized, that is it needs to work independent of input voltage polarity, and the DC to the locomotive reverses. This would destroy you typical cap like you mention. You only option is to power the frogs somehow. Again DCC makes this much easier, with DC you need a relay or toggle switch that actuates both the turnout and the polarity of the frog.


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## traction fan (Oct 5, 2014)

Murv2 said:


> I have a lot of really old engines that stall on my switch frogs because the wheelbase of the pickups is too narrow. Will a capacitor solve this problem? I googled it and found a recommendation for Tantulum 25V 100uF but they very quickly ended up too deep in the weeds for someone who doesn't understand electricity beyond 'flip the switch and it works'. My engines are old roundhouse, bowser, mantua and tyco kits and AHM diesels.


Murv2;

What kind of turnouts are you using? Do they have plastic frogs like the Atlas Snap Switch and Peco Insulfrog, or metal frogs like the Atlas Custom Line, and Peco Electrofrog? 
If they have plastic frogs, you're stuck, since they can't be powered. The alternative would be to add more pickups to the locomotives, so they have all-wheel pickup.

Traction Fan


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## Dennis461 (Jan 5, 2018)

Murv2 said:


> I have a lot of really old engines that stall on my switch frogs because the wheelbase of the pickups is too narrow. ...


Let's re-visit this problem. I had an 0-4-0T locomotive with a fairly rigid wheelbase. My turnout was not perfectly flat. So one wheel would roll on the plastic frog, and the other wheel on the same side would lift up off the copper rail.
Are your wheels and track really clean?


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## Murv2 (Nov 5, 2017)

Pretty sure it's just a narrow wheelbase. I'm using Unitrack and the number 6 switches have a substantial plastic frog. I'm thinking additional leads as well. Too bad, more work.


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## Sevenhills1952 (Feb 2, 2021)

I don't know if this is helpful or not, since I'm a retired (7 years) electronic technician, 43 years troubleshooting and had a company. 
Capacitors there are many types, tantalum and electrolytic are similar and polarized like a battery. They can be put in series to be non-polarized. In parallel the capacitance doubles (two 100ufd=200ufd), voltage stays the same. They have to be + to +.
Series capacitance is half (so two 220ufd=110ufd) but voltage doubles.
There are lots of other types, mylar, silver mica, paper, etc. Basically used to store or "smooth" electricity, pass AC (block DC), tune a circuit (pass filter), etc.
Clean track, good connections would be very important. 
It all ties into ohms law: E/IR
E (voltage)= I (current) times R (resistance)









Sent from my SM-S205DL using Tapatalk


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## Jscullans (Jul 8, 2019)

you could use super capacitors. But that’s a whole new ball of wax. They can last substantially longer than a standard cap. Super caps are almost like a short lived battery so they could end up going and not stopping for quite a while. I may have to order one and see what kind of damage I can cause with that


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## cid (Jul 3, 2014)

See Link < DC Keep-Alive >
A very interesting discussion and up-to-date solution on another forum. 😊


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## Murv2 (Nov 5, 2017)

One of the threads referred to talked about using a DCC decoder to smooth out power on the DC layout. (It's a funny thought, convert the DC input to AC, run it to the capacitors, when power dips feed it out of AC and convert back to DC). I put a query into the company referred to (TCS) to see if they can explain their brochure to a caveman. If I ever find a local club to run trains at the decoder would be a bonus. Never priced decoders...


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## DonR (Oct 18, 2012)

Have you looked into the possibility of adding to the
number of power pickup wheels. For example, you
might change the tender wheels of a steamer to
metal and wire them. If a small 4 wheel diesel, give
it a 'friend'...a caboose perhaps...with power pickup 
wheels.

Don


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## traction fan (Oct 5, 2014)

Murv2 said:


> One of the threads referred to talked about using a DCC decoder to smooth out power on the DC layout. (It's a funny thought, convert the DC input to AC, run it to the capacitors, when power dips feed it out of AC and convert back to DC). I put a query into the company referred to (TCS) to see if they can explain their brochure to a caveman. If I ever find a local club to run trains at the decoder would be a bonus. Never priced decoders...


Murv2;

If you get some reliable information that this works, or better yet ,a chance to test it, and verify that it works, please let us know. 
Meanwhile, there are other, probably much more practical, solutions to your problem. Neither one is cheap, but both have been proven, multiple times, to work. Your problem, of some locos stalling on a plastic, unpowered frog, is an old one that people have been experiencing for years.
You need either locomotives with all-wheel electrical pickup, or powered metal frogs on all your turnouts. 
By far the easiest, though an expensive, route would be to start gradually replacing your old locomotives that are stalling, with new locos equipped with all-wheel pickup. This means you don't have to change, modify, or do, anything except pay for new locomotives one at a time. Do you have any locomotives that don't stall on the frogs? If you do, the chances are that those locomotives have all-wheel pickup. You can test this by running one end of the locomotive off the end of a piece of track, and holding it to prevent the other end from running off the end. If the loco runs with only one of it's two trucks on the track, it has all-wheel pick up.

The other option would be to gradually replace your turnouts with some Peco Electrofrog, or Atlas Custom Line, turnouts. These have all-metal frogs that can be powered.
Electrically, a powered frog becomes just another piece of live rail that feeds power up to the loco's wheels like the rest of the rails on your layout. Replacing turnouts is also expensive, though probably not as expensive as replacing locomotives. In addition to cost though, replacing turnouts requires considerable work.

What brand, and type, of turnouts do you have now?
Are they Atlas "Snap Switches?" These come with a big ugly black plastic switch machine attached to the side of the turnout., and a black plastic frog.
Atlas's better quality "Custom Line" Turnouts come without a switch machine, and have a metal frog that can be powered. Peco "Insulfrog turnouts have a brown plastic frog. Peco's Electrofrog turnouts have an all- metal frog that can also be powered.


Some "Half measures."

These are lower cost, but far more troublesome, alternatives.

1) It's possible, (though a major PITA ) to "surgically" change the frog of a turnout through a "Frogectomy." Like any surgery, you first have to cut out the bad part. (the plastic frog.) Next, you insert the new part (a metal frog of your own making) and then connect up all the veins & arteries (rails and a wire) to get the new part to work. While this is possible, there is no doubt that it's extremely difficult, and the money, and turnout replacement labor, are small compensation for the effort of trying to save a probably not-so-hot turnout.

2) It's somewhat less trouble to do a "frog skin graft" than the full-on "Frogectomy" just described. This one involves adding brass angles to the inner walls, and top running surface, of a plastic frog. The angles should have a wire soldered into them on the inside surface of the angle. Then they are placed on the top of the frog with one side of the angle drooping down inside the outer wall of the frog's flangeway, and the other side of the angle on top of the frog. Tis will serve as the powered "rail" that the wheels will ride on.
A notch, and/or drilled hole, may need to be provided for the wire that is soldered to the inside of the angle.
However, if this modification is done to only the outside wall of the frog flangeway, and not the inner wall, you may be able to do away with the wire, notch & hole, and also with the micro-switch to change frog polarity. This greatly simplifies the procedure. 
Simply extend the brass angle far enough to connect to the point and/or wing rails on each side. The rails will feed power to the angles and the angles will feed power to the loco's wheels. Each angle will only feed power to its own route through the turnout. There will be no solid lump of a frog to need it's polarity changed to prevent short circuits.

3) Adding more pick up wipers & wiring to an old locomotive. Unless you're very emotionally attached to your old locomotive, this may not be worth doing either. It's a lot of work, but, done properly, its effective. The loco will sail right through an unpowered frog, if all it's wheels are powered.

Good Luck;

Traction Fan 🙂


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## Murv2 (Nov 5, 2017)

The switches are Kato Unitrack number sixes, they are pretty good and work with the entire system so I won't be changing them. I am emotionally attached to my old engines, they remind me of my dad's layout when I was a kid and I built many of them myself. I'll see what the manufacturer says and worst case, add more wipers. I've done that to a few of the tiny Bachmann engines and it worked pretty good so can be plan B.
Thanks for your input.


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## Lemonhawk (Sep 24, 2013)

Murv2, there is no AC to DC or DC to AC conversion going on in a Decoder equipped locomotive, the Decoder's rectifiers only correct the polarity of the incoming rail voltage. When a Decoder equipped Loco is put on a DC layout the Decoder is power by the Rail DC, which has to be above some nominal voltage before the Decoder will start working. If the decoder has a "Keep Alive" on it (caps) then it can start charging them but all this is done after the Decoder has run the DC power thru its rectifiers to convert the DC power to the correct polarity for running the Decoder and storing power in the the caps. When you reverse the DC voltage to make the Loco go the other way the decoder senses this and uses it as a signal to cause the decoder to drive the motor in the other direction. In no case is the Decoder converting any DC to AC. When the locomotive is on a DCC layout, the DCC control unit outputs a Pulse Width Modulated signal (PCM) by flipping the voltage on the rails just like a reversing switch does on a DC layout. The decoder uses the information generated by this PCM signal to control the locomotive. Its just with the DCC rail voltages the Decoder can get its power as soon as the rail power is turned on and the rectifiers in nanoseconds form a correct polarity out of this PCM rail power.


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## TomFromMo (Aug 9, 2016)

How about adding a second locomotive or adding a motor to a box car ? That might provide enough push to keep the lead locomotive moving forward before the 2nd locomotive hit the dead spots. This is probably a dumb idea for a reason I've not considered. Still kind of a newby myself.


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## traction fan (Oct 5, 2014)

TomFromMo said:


> How about adding a second locomotive or adding a motor to a box car ? That might provide enough push to keep the lead locomotive moving forward before the 2nd locomotive hit the dead spots. This is probably a dumb idea for a reason I've not considered. Still kind of a newby myself.


TomFromMo;

It's a thought, but what might happen is that the second locomotive would not be able to push the dead front locomotive once its motor and worm gear stopped turning. The boxcar, being so much lighter than a locomotive, wouldn't have a chance of pushing one. The powered boxcar would simply spin its own wheels.
What would work would be to permanently couple two locomotives and run power feed cables from one set of wheel wipers to the other. That way, the rear locomotive would still be on powered rails while some of the front loco's wheels were on the unpowered frog. The rear loco's wheels would send power up to the front loco and keep it running. This is simply a variation on adding more power pick up wipers to the locomotive.

Traction Fan


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## AmFlyer (Mar 16, 2012)

I have been following this, it is an interesting discussion of a common problem. The distance between pickups does not assure constant contact wih the powered rails. Space permitting, a solution to keep an engine moving for 1/8" to 1/4" is a flywheel on the motor.


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## traction fan (Oct 5, 2014)

traction fan said:


> Murv2;
> 
> If you get some reliable information that this works, or better yet ,a chance to test it, and verify that it works, please let us know.
> Meanwhile, there are other, probably much more practical, solutions to your problem. Neither one is cheap, but both have been proven, multiple times, to work. Your problem, of some locos stalling on a plastic, unpowered frog, is an old one that people have been experiencing for years.
> ...


Murv2

I'm going to contradict myself and most of what I've said above. You said you were using Kato #6 turnouts, and having some locomotives stall on the frog. Now I don't use Kato turnouts, and I have no personal experience with them. So I'm going to ask for help from people who do. It looks like Kato turnouts have metal frogs, and a previous thread indicated that those metal frogs were powered, and had their polarity changed by a set of contacts inside the turnout. If those things are true, I don't understand what is causing the stalls. A powered metal frog should pass power up into the locomotive the same as any other piece of powered rail does. So, if your locomotives run on the Unitrack, and presumably onto the turnout, along the point rails, and only stall when are on top of the frog, WHY? They shouldn't. So, all you Kato unitrack users, can you confirm or disprove the idea of powered metal frogs and polarity switching being present in the Kato turnouts? I'll admit I'm confused.


Traction Fan


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## Murv2 (Nov 5, 2017)

traction fan said:


> Murv2
> 
> I'm going to contradict myself and most of what I've said above. You said you were using Kato #6 turnouts, and having some locomotives stall on the frog. Now I don't use Kato turnouts, and I have no personal experience with them. So I'm going to ask for help from people who do. It looks like Kato turnouts have metal frogs, and a previous thread indicated that those metal frogs were powered, and had their polarity changed by a set of contacts inside the turnout. If those things are true, I don't understand what is causing the stalls. A powered metal frog should pass power up into the locomotive the same as any other piece of powered rail does. So, if your locomotives run on the Unitrack, and presumably onto the turnout, along the point rails, and only stall when are on top of the frog, WHY? They shouldn't. So, all you Kato unitrack users, can you confirm or disprove the idea of powered metal frogs and polarity switching being present in the Kato turnouts? I'll admit I'm confused.
> 
> ...


Remote Kato unitrack switches are metal frog, manual Kato unitrack switches are plastic frog. At least the number fours are, don't have any number six remotes.
I bought a KAM4-LED decoder from TCS and installed it in my AHM GP-7. Then I drove it across some of my favorite problem areas and it looks like it worked. Also, I can't swear for sure but it looks like the low speed performance of the engine has improved. The hot-wire light doesn't work. Lost a half ounce of weight. Now I'm trying to reassemble the engine and see what happens. I have another one, have to figure out what to put it in.

And oh yeah, I took the electrical pickups out of an AHM FM2 that I converted to a dummy and installed it in the live engine, that solved that.


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## Jscullans (Jul 8, 2019)

The biggest thing I’ve found with decoders is they tend to not like older open frame motors. Keep in mind most decoders have a 1 to 1.5 amp rating and a lot of open frame motors will stall out higher than that. That is why I swap all my brass engine motors to can motors so they’re a little smoother down low and also they draw less current


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## Chops124 (Dec 23, 2015)

I’ve asked the question, and was basically told that a capacitor the size of a cabbage would only be useful for my old DC junk. I watched the Keep Alive video all the way through, and unless they were straight out lying, they distinctly said their ultra small product was good for HO and N AND would work fine with DC? So, enlighten me, please, I am also not the sharpest tool in the shed.


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## Chops124 (Dec 23, 2015)

Murv2 said:


> Do those work with DC? I'm interested, think I could stick one in the tender...


That’s what Keep Alive says. I try to keep my track as clean as new penny, but on some stuff the electrical pick ups are cheap and flimsy, and no way will I get a flywheel into that.


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## Jscullans (Jul 8, 2019)

I know that the keep alive I have in my y6 is about 3/8 by 1.5 inches and it will keep it with sound running for 10 seconds after I shut power off to my layout. That one I believe is by digitrax


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## Lemonhawk (Sep 24, 2013)

The "Keep Alive" requires a decoder that has provisions for connecting a keep alive capacitor bank. Since you're DC, the decoder also has to work on both DC and DCC. And as mentioned before, the more current you motor takes the less "Keep alive" will work. Also on DC tracks the Keep alive only gets charged when the voltage is high enough to trigger the keep alive charging circuit. Biggest problem with older DC equipment is the high current motor and the complications of installing a decoder and "Keep Alive".


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## Jscullans (Jul 8, 2019)

You can buy 12 volt caps that will work good for a locomotive when it’s crossing insulated frogs to work as a flywheel. As far as keeping a locomotive running for much more than a second you would need a very large cap. The thing I would say is the biggest deal is the partial second you’re crossing a dirty spot in the track or an insulated frog. You don’t need anything too crazy to make it across insulated frogs or dirty track. If you have a bad turnout or something that could be causing some issues then the cap won’t help either at that point. Just a thought


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## Chops124 (Dec 23, 2015)

I got this vintage Triang Electra. It is surmised that it sucks up a lot of electricity. It likes to stall on diamonds, and judders a bit underway. I suspect old, and not terribly effective electrical pick ups, and I’d like to be able to run a little slower than 100 smph. This is a video of this otherwise cherished unit, even if it runs but fair.






She’s the electric with the extended pantographs. You can see how she hesitates upon turnouts and crossings, which eventually causes a derailment.


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## Jscullans (Jul 8, 2019)

If you can run the rocket on your layout and not that green 6 axle locomotive that tells me that you have either severely dirty wheels or you have some electrical pick ups that are just not functioning. I would see which pick ups are messed up and fix them before doing capacitors to the locomotive


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## Chops124 (Dec 23, 2015)

Yes, good idea.


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## Murv2 (Nov 5, 2017)

Jscullans said:


> If you can run the rocket on your layout and not that green 6 axle locomotive that tells me that you have either severely dirty wheels or you have some electrical pick ups that are just not functioning. I would see which pick ups are messed up and fix them before doing capacitors to the locomotive


I have a couple of the Bachmann pre-Civil war engines and I solved it for them by adding brushes to the engine drive wheels and attaching the wires to the tender drive. I need to run the GP a bit more to see if it is a final solution. There's one Atlas switch it really hates...


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## traction fan (Oct 5, 2014)

Murv2 said:


> I have a couple of the Bachmann pre-Civil war engines and I solved it for them by adding brushes to the engine drive wheels and attaching the wires to the tender drive. I need to run the GP a bit more to see if it is a final solution. There's one Atlas switch it really hates...


Murv2;;

On that "one Atlas switch that it really hates", doe the loco derail on that particular turnout, or does it stall? In either case, modifying that turnout (and perhaps, eventually, the others) with the information in these files may help.

Traction Fan 🙂


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## Jscullans (Jul 8, 2019)

I’m in the process of converting all of my atlas turnouts to peco. I personally don’t care if they look prototypical to American railroads I am just super impressed with how well they work. I’m going to leave a couple turnouts that I have ballasted but the rest are getting pulled up and replaced.


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## traction fan (Oct 5, 2014)

Murv2 said:


> I have a couple of the Bachmann pre-Civil war engines and I solved it for them by adding brushes to the engine drive wheels and attaching the wires to the tender drive. I need to run the GP a bit more to see if it is a final solution. There's one Atlas switch it really hates...





Jscullans said:


> I’m in the process of converting all of my atlas turnouts to peco. I personally don’t care if they look prototypical to American railroads I am just super impressed with how well they work. I’m going to leave a couple turnouts that I have ballasted but the rest are getting pulled up and replaced.


Jscullans;

If you're modeling in HO-scale, Peco has turnouts and track based on North American prototypes in HO. You might want to look at them as a possibility.
I model in N-scale, and the Peco N-scale turnouts are all based on British prototypes. The differences are not obvious when the turnout has been painted, and ballasted. Atlas "Snap Switch" turnouts don't bear much resemblance to the real thing either. In fact, the Pecos look a lot more realistic than the Atlas. If you want both highly reliable operation, and super-realistic resemblance to American prototype turnouts, check out Micro Engineering turnouts. They have both, and are also factory equipped with the DCC friendly configuration.

Traction Fan 🙂


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## Jscullans (Jul 8, 2019)

The peco turnouts I’ve bought over the last couple years seem like they’re different from the atsf main line turnouts but I guess I haven’t really ever paid real close attention when I’m walking the tracks. I’ll have to get pictures next time I go on an adventure for more tree making materials. I would also imagine that the turnouts have changed between the time I’m modeling and current day also. I started using small sticks that resemble trees instead of making my own armatures. They look better at least to me


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## traction fan (Oct 5, 2014)

Jscullans said:


> The peco turnouts I’ve bought over the last couple years seem like they’re different from the atsf main line turnouts but I guess I haven’t really ever paid real close attention when I’m walking the tracks. I’ll have to get pictures next time I go on an adventure for more tree making materials. I would also imagine that the turnouts have changed between the time I’m modeling and current day also. I started using small sticks that resemble trees instead of making my own armatures. They look better at least to me


Jscullans;

The use of new materials, like welded rail, concrete ties, and remote C.T.C. controlled motors replacing the traditional manual switch stand, has changed the appearance of modern turnouts. I don't think the basic design has changed all that much since the 1920s though. Yes the Peco British based turnouts do look different since their prototypes are different from American ones. However, reduced to HO or particularly N-scale, the 'bull heads" and "sleepers" the Brits use to construct their "points" don't show all that much. 

Using natural material for your tree trunks is a good idea. Nature duplicates itself in miniature, and some brush clippings and plant roots make great looking deciduous trees. I've never found a good naturally growing arbor for conifer trees though. The Miller's asparagus fern probably comes closer than most plants, but it's still too course for my taste. A disadvantage of using twigs is their brittle fragility. My layout is only 16" deep in most places, so it's pretty easy to come in contact with a model tree. I model the Seattle, Washington area , which has millions of conifer trees. I ended up making model conifers from cheap artist's-type paint brushes for the trunks and 3M Scotchbrite scouring pads for the branches. Takes a lot of work, but I think they came out well, and buying a forest of commercial trees would cost a fortune.

Traction Fan 🙂


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## Jscullans (Jul 8, 2019)

I’m not quite certain what exactly the plant I keep looking for is but I like the trees it makes. Unfortunately there isn’t much for tall trees here. You get big oak trees here and elm trees but they’re nothing like a conifer tree.


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