# A tale of 2 Aristo SD-45's



## BodsRailRoad (Jul 26, 2008)

I have an interesting problem with my 2 new SD-45's. The PRR one is the newest version and runs through every switch, at all speeds, with no issues. The Conrail I think is a first gen SD-45 and if I run through any switch at more than 50/128 it will derail. Both engines have the same amount of weights and as far as I can see are the same in every way except for the derailing problem. I tried both solo and pulling cars with the same results.

Is there some differance between first gen and second gen that would cause this issue? If so how do I go about fixing it, or should I just send the motor block back to Aristo?

Thanks for your help, Ron

2 Aristo Craft SD-45's


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## Greg Elmassian (Jan 3, 2008)

Actually, there appears to be different back to back spacing of the wheels. We have not determined if it's the axles or the gear, it's not the wheels. Upon measuring several locos, we have found that the first generation appears to be consistently "narrrower" back to back. Get a cheap vernier caliper and measure the back to back on your wheelsets. 

Regards, Greg


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## John J (Dec 29, 2007)

I would check your Wheel guage. See if the wheels are spaced properly. I was just up at Scan C's and I had 2 SD-45 There was a section of bad track. The first SD-45 had no prolem the second would derail. It would then re rail it's self when I hit the next switch.


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## NTCGRR (Jan 2, 2008)

Ones male , the other female.


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## BodsRailRoad (Jul 26, 2008)

Posted By Greg Elmassian on 27 Aug 2010 08:28 PM 
Actually, there appears to be different back to back spacing of the wheels. We have not determined if it's the axles or the gear, it's not the wheels. Upon measuring several locos, we have found that the first generation appears to be consistently "narrower" back to back. Get a cheap vernier caliper and measure the back to back on your wheel sets. 

Regards, Greg 

I did some measuring and found that the Conrails wheel back to back spacing was indeed narrower than the PRR's.

These are the Con's measurements in MM going from the front of the engine to the rear 1 being the first wheel set and 6 being the last wheel set .
1) 38.30, 2) 38.80, 3) 39, 4) 38.71, 5) 38.62, 6) 38.85

These are the PRR's
1) 39.26, 2) 39.16, 3) 39.18, 4) 39.16, 5) 39.50, 6) 39.40

Do you think that this is the problem, if so how do I fix it? What should the spacing be?

Ron


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## Randy Stone (Jan 2, 2008)

Posted By NTCGRR on 27 Aug 2010 08:34 PM 
Ones male , the other female. 
Is there any question as to which is which?

LOL


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## lownote (Jan 3, 2008)

I've "fixed' the back to back spacing on a couple aristo locos by filing down the inside of the flange, on the back of the wheels. I don't have a lathe or a milling machine, and so this is my crude method. 

Remove the block and set it spinning at high speed, take a dremel with a metal grinding tool to the back of the wheel. You could use a file as well. This will take some metal off the back and effectively change the back to back spacing while also thinning the flange. I told you it was crude!


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## Paul Burch (Jan 2, 2008)

Ron,
I believe at some point they also changed the position of the rigid axle in the motor blocks. If you rock the axles back and forth,one will be rigid and the other two should pivit. On the newer blocks the rigid axle should be the outermost axle on each end of the loco. Also if the loco is one of the very first release units look inside the block and check if the couplings between the gear housings are plastic or brass. The first units had plastic couplings. Later units were changed to brass.


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## Greg Elmassian (Jan 3, 2008)

What is should be is a complicated question, depends on who you ask and what standard and what tolerances you believe.

Here's a page with more than you want to know:

*http://www.elmassian.com/trains-mai...ainmenu-95*

The current NMRA spec says the target is 40.01 mm...


As you can see, all your wheels are narrow. 

Now, the tolerance is -.13 mm, so 39.88 mm... so you can see that the Conrail is still out.


Now, add in the sloppy guardrail flangeway widths, bad track gauge through the switch closure rails, and it's a wonder anything runs.

How to fix? not easy. Read my site:

*http://www.elmassian.com/trains-mai...inmenu-256*

There is all you could ever want to know about the Aristo power brick... go to almost the end, the section titled: *Weakness - Bad / non-adjustable wheel gauge*

Regards, Greg


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## aceinspp (Jan 2, 2008)

Yes they will vary. I have access to a lath and have taken some material off the back side of the wheels which will greatly improve the operation of the locos. Once you get the back to back measurements within the specifies tolerances all is fine. i also tend to make the flange a bit thinner as the the ones on the locos are much to thick. Later RJD


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## jmill24 (Jan 11, 2008)

Check the brake shoes, the early versions had the brake shoes rubbing the wheels so bad that the axles that are designed to swivel could not. Sometimes they could not swivel to a return position of being level. The fix is to remove side rails and grind shoes down with small drum sander on a dremel............Jim


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## Greg Elmassian (Jan 3, 2008)

Good tip on the restricted movement.

A picture of an early Aristo motor block, notice what narrow back to back can do? In severe cases the axles can be ripped out of the gear they bolt to.










Regards, Greg


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## BodsRailRoad (Jul 26, 2008)

Good tip indeed 2 of them were very tight.
I think I will send the motor blocks back to Aristo and get an exchange rather than mess them up myself if I can. 
If not then I'll dive in. Scott has alwaysbeen great to deal with on any issues I have had.

Thanks again guys for all the great info,
Ron


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## mgilger (Feb 22, 2008)

Ron,
By chance does your derailments always happen in the same direction and is it on the turnout (curved) side? 

I can't say I had the same problem, but it was simular and it was always happening going in one direction and into the curved turnout part of the swtich. I added a 12 inch strait section of track to my problem switch and the problem went away. I very seldom get a derailment at that switch.

So something else to ponder.

Mark


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## Greg Elmassian (Jan 3, 2008)

A good idea, but if your wheels are out of gauge, even by the Aristo gauge, then they are wrong, and you will never have reliable running. 

I'm so glad Aristo made an accurate gauge. If you read my page, you will see the comparison of standards against the gauge. 

If you are courageous you might want to try the Aristo gauge on your turnouts. Be sure you are in a good mood! 

Regards, Greg


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## eheading (Jan 5, 2008)

Paul, actually I've found that when you have less than perfect trackwork, my SD45 runs better with the "floppy" axle nearest the end of the loco. Another issue in the earliest versions of the SD45 was that some of them had the center axle "lower" than the two end axles. What I mean by this is that if you put the power block on the track it will pivot back and forth on the center two wheels; the outer two sitting just slightly higher than the center axle. This caused me some derailment issues too.

Ed


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## Greg Elmassian (Jan 3, 2008)

My chrome E8's also have the center axle lower... the problem has not gone away. I agree about this enhancing the ability to derail... have seen it as a direct cause. 

Greg


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## aceinspp (Jan 2, 2008)

Ed sounds to me like the motor was not seated right in the brick causing the high center effect. Easy to correct. And that means not reversing the trucks. Later RJD


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## eheading (Jan 5, 2008)

RJ, that was two different engines and two different engines. I did fix the "low center axle" on the early model of the SD45. I've mentioned this issue of the floppy axles before, I've found that on all my engines, either two axle engines or 3 axle engines, that they run much better on my less than perfect track with the floppy axle nearest the ends of the locomotive. I just got finished converting a new FA1 I recently purchased the same way. Does much better that way.

I know that you say if our trackwork was what it should be, we wouldn't have this issue, however, since many of us don't have good trackwork, and the design of the truck is such that it follows warp in the track much better with the floppy axle towards the ends, it just seems to me that all of the Aristo engines would work better if that were the way they are mounted.

Ed


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## jmill24 (Jan 11, 2008)

Well, Ed and RJ are both correct. With good track work the normal axle arrangement will work fine. The fixed axles really define the wheel base so when you flip them around so the fixed axle is inboard you shorten the wheel base so it will ride all the wheels in better contact with a twisted track. But what I don't understand is that I have run an E8, Gp40 and two SD45's on Ed's track with no problem. But now that I think about it, Ed always cleans up and does some track work before I show up. So what he needs is more visitors...............Jim


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## BodsRailRoad (Jul 26, 2008)

I thought I would update this thread with the results of my efforts.

I gave the 2 Conrail motor blocks to Navin at the fall ECLSTS and received the replacements Navin made for me in December.
I installed them last month and its first trial was a complete success, First Conrail SD45 trial (click me)
If it could handle that I'm sure the problem has been corrected.









Thanks for all your input and advice, Ron


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## Paul Burch (Jan 2, 2008)

Ron,
Glad they took care of it for you. I'm a bit curious though since there were quite a few changes made to the blocks between the first release and the current version. Can you tell if Navin actually rebuilt the old blocks or sent you different ones?


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## BodsRailRoad (Jul 26, 2008)

I'm pretty sure Navin built me 2 new trucks. He told me at the fall ECLSTS, when I gave him the 2 Conrail SD45 trucks, that he had the new transmissions and axles but that the complete units weren't due in until spring next year. He did a great job as usual, it'd be great if there were 50 Navins









Ron


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