# USAT Loco Shoes shorting LGB Turnouts



## Jerrys RR (Jun 28, 2010)

I believe I had read about this several years ago but until now it had not been a problem for me.

I have a USAT GP-38-2 and when I run it across one particular LGB R3 turnout the shoes (both front and back) short on the frog.

If I am not mistaken some people used paint on part of the frog but that would seem like it would wear off fairly quickly.

What do others do if they have this problem?

Thanks,

Jerry


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## Trains (Jan 2, 2008)

Take the shoes off, you don't need them.

Don


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## Greg Elmassian (Jan 3, 2008)

Absolutely 

Greg


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## W3NZL (Jan 2, 2008)

U can also re-shape, and narrow them a little if U want to run them, have several of them here that 
I did that to... As I remember the narrowing solved the shorting on LGB switches problem, and the 
reshaping solved the shoe dropping into Aristo switches problem...
Paul R...


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## Jim Agnew (Jan 2, 2008)

Make sure the shoes are bent at 90 degrees, some of the USAT shoes are over 90 degrees which causes them to catch or hang on the switch frog. You can also replace them with LGB shoes, which will solve the problem.


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## Jerrys RR (Jun 28, 2010)

Posted By Trains on 02 Jul 2010 06:13 PM 
Take the shoes off, you don't need them.

Don


Hi Don,

Sorry but I disagree strongly. A GP-38 without shoes would only have 8 track contacts (wheels). With shoes it has 12 track contacts (a 50% increase). 

In addition the GP-38 has traction tires (which I like very much). The rubber of the traction tires reduce the conductivity of the 8 wheels with the rails.

I am able to run the GP-38 and a NW-2 without conductivity problems on very tarnished brass track that has not been cleaned in many months.

While I cannot prove it I believe that the shoes also tend to clean the tracks as they run on them.

My GP-40's also run well but they do not have traction tires to limit their contact with the rails.

Regards,

Jerry


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## Jerrys RR (Jun 28, 2010)

Hi Paul and Jim,

I believe you have a good solution. I will look at the shoes and see if I can reshape them or narrow them to eliminate the problem. If all else fails I think I have a spare set of LGB shoes (I did not realize they would fit a USAT loco).

This particular turnout has the offside rail (in the frog) setting a bit high which makes it easy for the shoe to contact it but I prefer not to do anything to it as it is a lot easier to unfix a shoe than to unfix a hard to replace turnout.

Thanks,

Jerry


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## Greg Elmassian (Jan 3, 2008)

I'll have to refine my comment. 

The traction tires (which I know Jerry likes) do add traction, but put more strain on those axle with them. That leads to premature failure of the axles (the USAT cracked axle syndrome) 

So long ago I swapped all my traction tired axles out. This gave me more power pickup and allowed me to remove the troublesome "skates". 

By the way, the count of pickup wheels vs non should really be 4 with wheels alone (the traction tired wheels do not pick up power very well, the tires are insulators) 

So the comparison is 4 without skates and 8 with, a 100% increase. 

My opinion is keep the skates if you must have the traction tires, lose the skates if you do what I do and hate the skate problems, looks and cracked axles. 

Regards, Greg


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## Joe Mascitti (Oct 30, 2008)

I had this problem...the quick fix is to put a piece of electrical tape over the short rail after the frog. The real fix is to take the turnout out, look underneath and see if the metal strap is broken. The electrical tape fix lasted for months until I removed the turnout. 

Hope this helps


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## Jerrys RR (Jun 28, 2010)

Posted By Joe Mascitti on 03 Jul 2010 11:29 AM 
I had this problem...the quick fix is to put a piece of electrical tape over the short rail after the frog. The real fix is to take the turnout out, look underneath and see if the metal strap is broken. The electrical tape fix lasted for months until I removed the turnout. 

Hope this helps 



Hi Joe,

If the strap turns out to be broken is there a way to fix it?

Thanks,

Jerry


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## Joe Mascitti (Oct 30, 2008)

Hi Jerry...


Just re-solder or solder a jumper wire..that should do the trick


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## Jerrys RR (Jun 28, 2010)

Posted By Joe Mascitti on 05 Jul 2010 03:17 PM 
Hi Jerry...


Just re-solder or solder a jumper wire..that should do the trick





Hi Joe,

That had not occurred to me as possible. The LGB turnout straps appear to have been welded. I do not know how they did it and I did not think they could be soldered back without melting the plastic parts.

Thanks,

Jerry


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## Greg Elmassian (Jan 3, 2008)

I'm a little confused. 

The shorting is caused by the shoe touching the "wrong" rail just past the frog. 

Adding some tape to insulate the rails stops the short. 

But some people might disconnect the power to the short "frog rails" entirely. That makes sense, and I've seen it. 

But why would ENSURING that the frog rails were powered help? Seems to be going in the wrong direction. 

Regards, Greg


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## Cougar Rock Rail (Jan 2, 2008)

Jerry, 

Also make sure the problem turnout is perfectly level...I've seen that cause problems, and it can ensure the short wheelbase locos get through more cleanly & without hesitation. 
My suspicion, though, is that Jim's comments are correct on the slider shape...I'd replace them with LGB ones. I even had this problem with a brand new LGB loco--turned out the sliders were just slightly different from previous ones...not sure why, but when I changed them the problem went away. 
I agree on keeping the sliders....I sure don't notice them and they do a great job of picking up power and minimizing arching. 

Keith


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## Jerrys RR (Jun 28, 2010)

Posted By Greg Elmassian on 06 Jul 2010 10:18 AM 
I'm a little confused. 

The shorting is caused by the shoe touching the "wrong" rail just past the frog. 

Adding some tape to insulate the rails stops the short. 

But some people might disconnect the power to the short "frog rails" entirely. That makes sense, and I've seen it. 

But why would ENSURING that the frog rails were powered help? Seems to be going in the wrong direction. 

Regards, Greg 

Hi Greg,

The rails need to have power - they are too long to leave without power. The shoe contacts both of the rails as it crosses the frog.










My thought was that if the rail had become disconnected from the conductive bar it might have allowed the rail to rise up higher than normal.










I don't think that is the case here. Instead I believe the shoe must be at too much of an angle because another USA loco has no problem with the same turnout and the original loco crosses over different LGB turnouts with no shorting.

In my opinion the "problem" came up because of the sensitivity of my Aristo Everest Power Supplies. They tripped and at first I thought I had a defective power supply but when the 2nd one also tripped I watched the ammeter and saw it spike. My other power supplies may not have reacted as quickly to the short allowing the loco to pass the short before it tripped the breaker.

I ran a NW-2 repeatedly over the turnout with no indication of a short which convinced me that I need to bend or replace the shoes/sliders and that should fix the problem.

Sometimes an obvious solution is not obvious when we have not run across it before (or recently when our memory is not very good).

Regards,

Jerry


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## Jerrys RR (Jun 28, 2010)

Posted By Cougar Rock Rail on 06 Jul 2010 11:00 AM 
Jerry, 

Also make sure the problem turnout is perfectly level...I've seen that cause problems, and it can ensure the short wheelbase locos get through more cleanly & without hesitation. 
My suspicion, though, is that Jim's comments are correct on the slider shape...I'd replace them with LGB ones. I even had this problem with a brand new LGB loco--turned out the sliders were just slightly different from previous ones...not sure why, but when I changed them the problem went away. 
I agree on keeping the sliders....I sure don't notice them and they do a great job of picking up power and minimizing arching. 

Keith 

Hi Keith,

I agree that the slider shape is the problem. I will try reforming it and if that does not work I will replace it.

Regarding the benefit of the sliders the importance of it was "illuminated" for me a few nights ago. I was running a train in semi-darkness with a USAT loco with sliders and a USAT caboose.

As the train ran around the layout the loco ran perfectly with no indication of lack of conductivity (the loco lights never blinked). On the other hand the caboose ran perfectly lit on the recently installed stainless steel curves but blinked furiously as it traveled over the old brass track that has not been cleaned for months.

If I had been running an 0-4-0 (the equivalent of the caboose with 4 conducting wheels) without sliders the loco would not have made it two feet on that brass track yet the USAT NW-2 with 8 wheels and 4 sliders or a USAT GP-38 with 8 wheels (including 4 wheels with traction tires) and 4 sliders have no difficulty running on the dirty track.

I suspect that many people give up on brass track and switch to battery power simply because they tried to run on dirty brass track with too few wheels or sliders making electrical contact with the rails.

In the past it was not at all uncommon for me to find up to 50% of the carbon brushes on my (former) Annies to NOT be making contact with the drivers of the loco. Often the springs had failed or the housing had caught the carbon insert and prevented it from moving. Additionally many less expensive locos have rigid frames that do not allow the drivers to float on track that is not perfectly level. This results in the loco rocking on the rails with a further reduction of track contact of 50% or more.

Locos with drivers that float on the rails and sliders that also float on the rails will run on track that other locos are unable to run on. Anything we do that reduces the electrical contact with the rails is going in the wrong direction (in my opinion).

Regards,

Jerry


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## AppleYankee (Jan 3, 2008)

Just to add to the confusion, I have a USA NW-2 that was having trouble on one or two of my switches (R1's). I swapped the sliders on the motor blocks. right side for left side, etc. Problem went away. 

Jan


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## Greg Elmassian (Jan 3, 2008)

Jerry, many people with Aristo steamers had problems, and gave up on track power, and it has been determined that the locos pick up from EITHER the loco or the tender, but not both at the same time!!! 

Even my mallet ran better with the tender wired to pick up on all wheels and connected to the loco. 

And this was on SS track. 

I have removed all my sliders on my USAT locos, but with SS track, no oxidation, and traction "wheels" swapped out for "conducting" ones, I get great power pickup without the sliders. 

Without doing these mods, or running on poorly cleaned track, I agree, keep the USAT sliders, but you could still be in trouble with Aristo. (the diesels have their own set of pickup problems) 

Regards, Greg


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## Chucks_Trains (Jan 2, 2008)

USA has a updated slider for the PA's that I'm sure will work, it's shaped a little different and a bit narrower.

I'm in the traction tire & slder camp and have never had a problem. 

Personally I think that it's more of a factory assembly/manufacturng problem with cracked gears that "train stress"..why else would USA Trains be inspecting all S-4 motor blocks before they shipped out?? Those engines were never "stressed" in actual use but USA inspected them all before shipping.


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## Greg Elmassian (Jan 3, 2008)

I agree on the cracked gears, the plastic used, and the diameter of the half axles cause the cracking. 

I have bought a number of NOS USAT locos and I check them before running. A recent 44 tonner had 7 cracks in the 8 potential locations. 

I have changed out the traction tires in my "theory" about evening the load between the wheels. Before I changed over, the great majority of the "cracked gears" on my locos was on the traction tired wheels... therefore my "theory". 

Regards, Greg


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## Jerrys RR (Jun 28, 2010)

Posted By Greg Elmassian on 07 Jul 2010 12:07 PM 
Jerry, many people with Aristo steamers had problems, and gave up on track power, and it has been determined that the locos pick up from EITHER the loco or the tender, but not both at the same time!!! 

Even my mallet ran better with the tender wired to pick up on all wheels and connected to the loco. 

And this was on SS track. 

I have removed all my sliders on my USAT locos, but with SS track, no oxidation, and traction "wheels" swapped out for "conducting" ones, I get great power pickup without the sliders. 

Without doing these mods, or running on poorly cleaned track, I agree, keep the USAT sliders, but you could still be in trouble with Aristo. (the diesels have their own set of pickup problems) 

Regards, Greg 

Hi Greg, 

I have an unconfirmed suspicion that some of the conductivity issues with the Aristo diesels may have to do with the distributed weight per wheel contact. With my SD-45's and especially the E-8's I had a serious problem driving (especially the E-8's) through my freight yard of LGB R3 turnouts. This was even when I MUed the E-8's.

The problem was apparently resolved when I added the Aristo lead weights to the E-8's and SD-45's. I suspect that without the weights all of the wheels were not maintaining good contact with the rails. In effect the higher quality design (in my opinion) of Aristo using a metal backbone with the frame of their locos may contribute to the frame not bending slightly to allow the trucks to follow the contour of the rails (the USAT diesels I have do not have such a metal backbone). 

On the other hand I was surprised and disappointed to discover that the MU connector on the SD-45's and E-8's does not work with track power. The MU connection is only powered when under battery power. I do not understand this. Long ago I MUed all of my Aristo FA/FB-1's and I could run a ABBA set on track that had not been cleaned in over a year. This was easy because the ABBA set had 32 interconnected track contacts. With 16 traction tires those ABBA sets could probably pull a brick out of a wall!

In fairness we get what we pay for. My oldest Aristo steam locos had rough cast drivers that made contact with the carbon brushes and with the rails more problematic than my more expensive LGB Moguls with polished plated wheels that provided excellent contact both with the carbon brushes and with the tracks. Even within LGB the 2-4-0's (as expected) do not have equal track contact as the LGB Moguls and even LGB wiring can be strange such as Forneys with switches that turn off one of the trailing truck contacts.

In truth sometimes the best solution for some is battery power but for those like me who prefer track power we just need to pay a bit more attention to how good and how many track contacts we have.

Jerry


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## Jerrys RR (Jun 28, 2010)

Posted By Chucks_Trains on 07 Jul 2010 02:29 PM 
Personally I think that it's more of a factory assembly/manufacturng problem with cracked gears that "train stress"..why else would USA Trains be inspecting all S-4 motor blocks before they shipped out?? Those engines were never "stressed" in actual use but USA inspected them all before shipping. 

I agree. I have a brand new (a few years old but never installed) NW-2 motor block. I took it apart trying to figure out how to put traction tires on it and I discovered that both gears were split - and this was on a motor block that had never been used.

There obviously is a quality issue with the gears of the NW-2. It may be the quality of the plastic or an inability to handle the stress once forced over the splines of the axles. I suspect than if I looked at them I would find at least 50% with split gears.

In fairness I have never had USAT refuse to replace a defective part.

Jerry


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## Trains (Jan 2, 2008)

When I was track powered, I took them off all my USA engines and never had any problems. At that time I had about
10 LGB 1600 switches on the layout.


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## Jerrys RR (Jun 28, 2010)

The problem with the shoes shorting on the LGB turnouts seems to have been fixed when I bent the shoes on the first USAT loco but then it returned when I started running a NW-2. Strangely the NW-2 and the GP-38 have shorting problems on totally different turnouts and each worked fine with the turnout that caused problems with the other.

I then used a LGB Corpet Louvet loco and naturally it ran fine across all of the LGB turnouts.

Jerry


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## Greg Elmassian (Jan 3, 2008)

Belated reply to your E8's and R3 switches. That's 8' diameter switches, pushing the limit on the E8's Jerry. 

If you took the sideframes off and watched your E8's roll through the switches, you would probably see them try to climb out of the switches, and adding weight helped. If your switches were on any kind of grade or crosslevel problem that would explain it. 

On 3 axle Aristo locos, the truck assembly is basically rigid in the up and down direction. The axles slide from side to side to accommodate sharper curves (although the worm gear takes a bias from the torque and angle of the teeth) but that does not help on humps and dips. Likewise, the ability of the gearboxes to "twist along the long axis" only helps when you have a twist in the rails. If your rails are not twisted like a corkscrew, then this freedom means nothing also. So humps and dips will try to life the wheels off the rails. The only thing that keeps 3 axle Aristo locos on the track is the extreme flange depth. 

Take the time to take the 2 screws off a sideframe and watch the wheels go out of contact. You will see that a lot of the time you are riding on 2 axles. Try it and you will see the truth of it. 

On USAT diesel locos, when the chassis is screwed to the body with 10 screws, the entire structure is rigid. Yes the flexibility of the chassis by itself is unsettling at first. It does not make any difference anyway, because the trucks are free to rotate, swivel and rock, so the chassis has nothing to do with it, i.e. the amount the trucks can move is much less than any deflection of the plastic near the truck mounting. 

Just a few comments on what I have observed. At first I had the same observations as you posted earlier, but upon further investigation, I learned what I posted here. 

Regards, Greg


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## Jerrys RR (Jun 28, 2010)

Posted By Greg Elmassian on 13 Jul 2010 09:44 AM 
Just a few comments on what I have observed. At first I had the same observations as you posted earlier, but upon further investigation, I learned what I posted here. 

Regards, Greg 

Hi Greg,

I had come to the same conclusions.

In many ways the hobby is moving away from what I had come to like. Now everything tends to be focused on battery power, large locomotives, large trains, wide sweeping curves etc. etc. etc.

This is OK with me as I have built and bought about as much as I need and have space for plus I figure the manufacturers need to make whatever it is that they think the market wants to buy.

Perhaps the difference is that I like a lot of switches (turnouts) which give me a variety of operational choices in the limited spaces I have to work in. This calls for relatively smaller curves (in some cases 4' diameter). 

What has evolved has been that my outside layouts have become pretty much Aristo diesel layouts while my indoor layouts have remained primarily LGB Steam layouts. 

The new focus seems to be on big modern trains but my interests remain primarily late steam and first generation diesel.

The change may be due to newer generations of large scalers who grew up after steam had passed into history.

Jerry


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## Greg Elmassian (Jan 3, 2008)

Jerry, one thing to be sure of on Aristo 3 axle diesels is keeping some oil on the axles. Since they have to slide sideways in sharp turns, and the fit between the axle and the inner race of the ball bearings in the gearboxes is necessarily "close", oil on them is essential to have them work properly. 

The grease in the gearbox is concentrated on the gears, and since it is grease, it does not naturally flow to lubricate these areas. 

Believe it or not, I recommend a "heavy gear oil", since it seems to be "tackier"... Hob E Lube is my choice here. 

Regards, Greg


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## Jerrys RR (Jun 28, 2010)

Hi Greg,

Thanks for the suggestion.

Jerry


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## Jerrys RR (Jun 28, 2010)

A MoPac PA/PB set arrived today and I noticed extra shoes (sliders) in the packaging. Then I found this note:









--

Apparently USA Trains is aware of the problem with LGB turnouts and has come up with a solution for it.

Thank you USAT.

Jerry 
PS I was surprised to find that the motor blocks of the PA and PB are articulated. Two axles are fixed and the third axle pivots. It should do fine on my R3 curves and turnouts.


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## Jim Agnew (Jan 2, 2008)

Jerry, make sure you slip shims (I use tongue depressers) between the bottom of the motor block and the mainframe to keep the bearings seated before you remove the top plate.


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## aceinspp (Jan 2, 2008)

Jerry are you units the newer versions? Later RJD


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## Jerrys RR (Jun 28, 2010)

Posted By Jim Agnew on 22 Jul 2010 05:13 PM 
Jerry, make sure you slip shims (I use tongue depressers) between the bottom of the motor block and the mainframe to keep the bearings seated before you remove the top plate. 
Hi Jim,

I'll try to remember that. So far the PA/PB have gone around the outside of the layout without any problems. I am hoping I won't have to mess with the new shoes but to instead use them on other USA locos like the NW-2 and GP-38 that have been giving me problems. 


I've never seen much less worked on this type of motor block before.

Thanks,

Jerry


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## Jerrys RR (Jun 28, 2010)

Posted By aceinspp on 22 Jul 2010 05:44 PM 
Jerry are you units the newer versions? Later RJD 
I did not know there were older and newer PA versions. I don't think I had ever seen a PA or PB before (at least I never looked at one closely). I mainly bought them because they were cheap (on eBay) and they were MoPac and anything MoPac is very hard to find.

How would I know if they are old or new versions?

Jerry


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## Greg Elmassian (Jan 3, 2008)

Jerry, another USAT 3 axle tip is grease the plate with the curved slot for the floppy axle... usually they are dry as a bone, and the "floppy axle" does not slide side to side freely. You will notice that the plated finish of this plate is rough, not smooth, which further contributes to this lack of "flexibility". 

Regards, Greg


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## Jerrys RR (Jun 28, 2010)

Posted By Greg Elmassian on 22 Jul 2010 08:22 PM 
Jerry, another USAT 3 axle tip is grease the plate with the curved slot for the floppy axle... usually they are dry as a bone, and the "floppy axle" does not slide side to side freely. You will notice that the plated finish of this plate is rough, not smooth, which further contributes to this lack of "flexibility". 

Regards, Greg 
Hi Greg,

Do you mean the metal plate with the curved slots in it?

Thanks,

Jerry


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## Greg Elmassian (Jan 3, 2008)

Please read (at least) the "Tips and Modifications" on my PA page:

*http://www.elmassian.com/trains-mai...ainmenu-83* 


Regards, Greg


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## Jerrys RR (Jun 28, 2010)

Posted By Greg Elmassian on 23 Jul 2010 08:19 AM 
Please read (at least) the "Tips and Modifications" on my PA page:

*http://www.elmassian.com/trains-mai...ainmenu-83* 


Regards, Greg 


Hi Greg,

All the PA/PB's I received have very floppy pivoting drivers and the metal plate seems quite smooth. Perhaps USAT changed it.

I have not run them much yet but they seem to be getting along with my LGB turnouts. So far the only problem has been an ABA with one of the A units uncoupling (hook and loop couplers) on a high point of the track where the plywood under it has buckled a bit. That will be an easy fix.


The main thing that makes me uncomfortable is how very flexible the plastic frame is without the top attached. It would be nice if it had a metal backbone like the Aristo locos do. Still, every manufacturer has some things I like (like shoes, articulated motor block and traction tires) and other things I would like to be different. 


Since I will be carrying these PA/PB's a lot, the traction tires are preferable to more weight to increase the traction. 


Regards,

Jerry


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## Greg Elmassian (Jan 3, 2008)

Yep, it feels like the frame might even crack in two with all the weight at the ends. Once it is buttoned up, it's perfectly rigid though. 

Grease up that plate though, under pressure (like when on the track) it can hang up. 

Enjoy them! 

Greg


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## Jerrys RR (Jun 28, 2010)

So far no problems with the PA/PB's on the LGB turnouts so maybe I'll be able to use those extra shoes on the USAT NW-2 and GP-38 that were giving me problems.

On the other hand I noticed that an ABA set with two Sierra sound systems is pushing close to 8 amps (just the locos). It will be interesting to see what happens to the amps when I add some lighted coaches.

Jerry


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## Greg Elmassian (Jan 3, 2008)

Jerry, is that on level track and no load? 

Greg


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## Jerrys RR (Jun 28, 2010)

Posted By Greg Elmassian on 23 Jul 2010 10:14 PM 
Jerry, is that on level track and no load? 

Greg 
Hi Greg,

Yes it is. I suspect (but did not measure) the Sierra sound units are taking perhaps an amp each. I also think that when MUing the ABA set the traction tires may add a bit to the overall amps (perhaps 1/2 amp total) as the locos may not all want to run exactly the same. I did run the three locos on the track but separated and the amps might have been 1/2 amp less but it is hard to tell.


Another factor is that I was running the UP ABA set on the inner loop which has some old track that has not been cleaned in a long time.


Just to see what happened I added a MoPac pair with a single old Aristo (PH Hobbies) sound system in the "A" unit on the outer loop (which has both newer brass and stainless steel track) and the amps did not go over 10. This is based on the ammeter on an Aristo Everest power supply.

By comparison this morning I ran my old Warbonnet F-1 ABBA (with 4 LGB analog sound systems) pushing a G Clean track cleaning car around the layout and never got up to 5 amps. Those locos when pulling a dozen Aristo Streamliners pull around 10 - 12 amps. Batteries would not last long.


The PA's ran well but with the heat (both air temp which was in the high 90's and the track temp which was too hot to touch) had the grease flowing between the axles and journals. I am amazed these plastic trains hold up so well in the heat.

It is possible that part of the issue may be dirty track in that when I first put the F-1's on the track singly their lights would flicker a bit. A single FA-1 with traction tires (in my opinion) really needs a FB-1 MUed to it to assure good track contact on dirty track.


I fill the LGB 50040 cleaning block in the G Clean Track Cleaner with lead bullets, wet the pad with LGB Track Cleaning Fluid and use the F-1 ABBA to push it around the track including in and out of the sidings. Its not as good as the LGB Track Cleaning Loco but it is more fun than work.


Tomorrow morning I will try running "the cleaning train" again but this time with an Aristo Long Steel Caboose with external marker lights. The caboose I used this morning had interior lights only so I could not see the lights flickering. The combination of a Track Cleaning Car in front of the ABBA followed by a lighted caboose gives me the cleaning action up front and the lights on the caboose to tell me how clean (conductive) the track really is. 


Regards,

Jerry


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## Greg Elmassian (Jan 3, 2008)

Dirty track will reduce amp draw, not increase it, because of the extra resistance in the circuit. 

V = IR ... increase the resistance (R), leave the voltage the same (V) and algebra tells you that the current (I) must decrease. 

Maybe it might be more intuitive expressed as I = V / R ..... increasing R reduces I (you are dividing V by a larger number)... 

I concur that the Sierra units are drawing a fair percentage of the overall current. The older sound hardware is not very efficient. 

Regards, Greg


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## Jerrys RR (Jun 28, 2010)

Hi Greg,

I used your web site to identify the connectors USAT uses so a friend can order them to make installation of a Revolution easier (no cutting and splicing wires). They are a LOT cheaper than what I have been paying for them.


Thanks for making the info handy. 


Jerry


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## Jerrys RR (Jun 28, 2010)

Posted By Greg Elmassian on 24 Jul 2010 01:08 PM 
Dirty track will reduce amp draw, not increase it, because of the extra resistance in the circuit. 

Regards, Greg 
Hi Greg,

That may be true regarding Ohm's law but Ohm was only referring to electrical resistance and not to mechanical resistance (drag).

What I meant was that since the USAT PA/PB's are not MUed electrically and because they have traction tires, I believe that momentary interruptions in current flow to a locomotive's motor due to irregular contact with dirty track will result in an irregular push-pull between the locomotives in the consist. With traction tires this can be quite noticeable especially with something like my old FA/FB-1's since they have 8 contacts (wheels) but half of those have traction tires resulting in (at times) as little as 4 track contacts. Four separate FA/FB-1's running on dirty track will have a very noticeable hesitation as they move around the layout but once I MU them together they will run on the dirtiest track without the slightest hesitation.


I did notice a slight increase in the amps drawn by the PA/PB ABA set when MUed together as compared to running separate but at the same time on the same track. It is speculation on my part but I believe the cause for the difference is the increased drag (mechanical resistance) demanding increased current to overcome the drag - just as an uphill grade will increase the amps needed to climb it.


Even on perfectly clean track I would be surprised if there was not a slight increase in amps just due to the typical variations in electrical motor performance from one motor to another. If 6 motors in a 3 loco consist are forced (by the traction tires) to maintain identical rpms I would think there would be friction generated resulting in some lost efficiency.


Regards,

Jerry


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## Greg Elmassian (Jan 3, 2008)

I believe that the engine not "dropping out" could increase it's amp draw when it has to pull a loco "temporarily dead" 

BUT 

This is most likely almost exactly offset by the fact that the other loco is not drawing current at the time. 

Most likely this is a wash, in fact, probably less current draw. 

Why? 

Try this experiment... take 2 identical locos. Pull a train with one, note amp draw at voltage. 

Now take just one of the locos, pull same train at same voltage, note that the amp draw is about double, but not quite. 

Because you are doing the same "work" no matter how many or few motors you have hooked up. 

Actually the multiple loco setup will be slightly less efficient since there are more electrical losses in 2 locos than one, more lights, losses in internal power supplies, and more rolling friction. 

Finally, since you are talking USAT PA's you CANNOT force them to maintain identical rpms, you cannot make the motor turn by pulling the loco. It does not have that design of gears. 

Bottom line, looking at it from all these different angles, I stand on my generalization, if anything you will pull less amps, because you will be doing less "work" because of intermittent power. That's the overall point, less work less power used. 

Regards, Greg


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## Jerrys RR (Jun 28, 2010)

Hi Greg,

You are the engineer not me. My opinions are impressions based on what I observe and the equipment I measure with is not of a quality I would consider accurate enough to base conclusions on. If I was pushing the limits of my equipment I would be concerned about it but until I put a load of streamliners behind the locos the amps are not a significant issue for me.


Regards,

Jerry


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## Jerrys RR (Jun 28, 2010)

I had an eye-opener today. The PA/PB/PA's were drawing around 8 amps. When I added 9 aluminum cars the amps went to 10. Then I turned the coach lights on and the amps went to 15 at around 24 volts and the MAG-15SR circuit breaker popped.

This was at only a moderate speed. With 2 more coaches coming it looks like I will need a new power supply before fall when it starts getting dark early and I start running trains in the dark again.

I guess it proved Greg's comments regarding Ohm's law (not that I disputed it) in that when the train was far away the volts and amps were lower but as the train got close to me and to the power supply the amps steadily increased until the breaker flipped. Since I only use a single feeder wire and few clamps it is logical that the resistance to the train dropped increasing the conductivity (and amps) to the train.

Jerry


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## Greg Elmassian (Jan 3, 2008)

Yep, Ohms law is pretty hard to ignore, ha ha. I guess that's why the call them "laws" rather than "suggestions" or "approximations", or whatever. ;-) 

About 1/2 amp each not too bad. My USAT ones drew at least .7 amp, but at my 24 volts dcc constant voltage. You were probably running a lower voltage, and lamps consume less (and are dimmer) at lower voltages. 

Good case for LED lighting. Just like using a sound system that is more expensive than the loco bothers you, rolling stock that uses more amps than the locos bothers me! 

Regards, Greg


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## Jerrys RR (Jun 28, 2010)

Posted By Greg Elmassian on 25 Jul 2010 04:09 PM 
About 1/2 amp each not too bad. My USAT ones drew at least .7 amp, but at my 24 volts dcc constant voltage. You were probably running a lower voltage, and lamps consume less (and are dimmer) at lower voltages. 

Regards, Greg 

You are right about constant 24 volts DCC voltage. They are USAT cars and I could run at around 20 volts but any higher and the breaker flipped. Just for the heck of it I switched from the MAG-15SR to an Aristo Everest with 15 amp controller. For some reason the train seemed to run a bit faster but again the breaker popped (as expected). Once I switched the lights off everything ran fine as fast as I wanted (not much faster than when the breakers popped).

After pricing some 20 - 25 amp power supplies I may need to plan on slower running in the dark.

Jerry


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