# USA Train SD70Mac



## Large Scale Mark (Apr 11, 2013)

I have a question, the coupler on the back of my USA train engine broke off, is there an easy way to fix this...


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## chuck n (Jan 2, 2008)

Call Charles Ro in Malden, Ma. They are the manufacturers for USA Trains. Unlike some other LS manufacturers, they are usually very good with spare parts. Chuck


*Charles Ro Supply Company*
662 Cross Street
P.O. Box 100
Malden, MA 02148
* 1-800-225-4425*


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## Greg Elmassian (Jan 3, 2008)

Mike is the name of the most knowledgeable guy in parts, in my opinion, I always ask for "Mike in parts" 

Likewise great experience with them. 

Greg


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## SD90WLMT (Feb 16, 2010)

After you call Mike in parts to place your order, .... 
....remove the front coupler assembly, install it at the rear of the loco.. 

Then go run your trains while you wait for parts to come to your door. 

Welcome here to MLS... Have fun with your trains!!! 

Good luck...Dirk. - DMRR & DMS Ry.


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## Dick413 (Jan 7, 2008)

What part of the coupler broke? it might be a good time to change to KD and yes welcome to MLS


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## chuck n (Jan 2, 2008)

Dick, I'm not home now to check for sure, but I don't think that there is an easy Kadee fix. I think that you need a long shanked coupler, like the USA knuckles. I replaced the stock ones with USAt step up couplers. Unfortunately, the stock coupler height is at the truck mounted height, too low to mate with all my body mounted Kadees. Chuck


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## Greg Elmassian (Jan 3, 2008)

Ted Doskaris has an article that goes into depth on the SD70, including mounting Kadees.


*http://elmassian.com/trains/motive-...c-vignette*

Greg


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## chuck n (Jan 2, 2008)

Greg, Ted's article is very informative, but for my trains, the USAt offset coupler does the job. Somewhere between my 15 car max and your longer trains they may fail. The USAt offset is an easy swap. Ted's approach while elegant, isn't, at least for me viable solution. It might help this discussion if the OP mentioned how the coupler broke: pulling a long train (how many cars), dropped, or backed into a standing train too fast, etc.? Chuck


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## Large Scale Mark (Apr 11, 2013)

It broke while pulling about 9 cars, I will try and post some pictures.


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## Large Scale Mark (Apr 11, 2013)

I don't know how to add Pictures or a PDF file


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## chuck n (Jan 2, 2008)

I'm surprised that it broke with 9 cars. Are they heavy, do you have steep grades, or sharp curves (less than 10' diameter)? Chuck


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## Large Scale Mark (Apr 11, 2013)

I run mine on 8 foot diameter curves, I have a dummy GP30 behind the SD 70 Mac and some other USA cars like 2 4 bay hoppers and a caboose, the rest are Bachmann car not that heavy.


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## Large Scale Mark (Apr 11, 2013)

So I called Charles Ro, and it is not good news, looks like I am going to have to pull out the old screws drill out the hole and input a longer scew with a nut, anybody very have to do this?


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## chuck n (Jan 2, 2008)

Mark:

I am not surprised that you had problems, 8' diameter is awfully tight for that engine. That is why I ask the question earlier. I have trouble with my SD70 mac on my 10' diameter curves. I have to pick and choose the trailing cars carefully. Otherwise they are pulled off the track when entering a curve. I have the same problem with my GG1. They are very long engines with a lot of body overhang. I do not have problems with USAt stream liners and freight cars with body mounted Kadee 830s. Truck mounted couplers do not swing far enough out to keep the front truck on the track. You will have to do more than just replace the coupler. I suggest putting the longest shanked coupler you can find on the GP 30 and make sure it can swing left and right. You may have to use a make shift wire connector to extend the distance between the two engines.

Here are some pictures of the engine and some cars on the 10' d curves.

Engine only center line swings out past the outside rail.









engine coupled to 40' box car with body mounted #830.

Note that the engine coupler is as far in as it can go and the box car is as far out as it can go.












engine with USAt postal car. In this case the couplers swinging is the opposite direction from the previous picture.










I think that you are putting tremendous torque on your coupler assembly.

I suggest that when you get the coupler fixed that you position the engine and the GP30 on the track and carefully look at how the couplers interact as they enter the curves.

Chuck


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## Large Scale Mark (Apr 11, 2013)

I don't use those coupler I use the other one for the smaller curves


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## chuck n (Jan 2, 2008)

Are you using hook and loops? Chuck


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## Large Scale Mark (Apr 11, 2013)

Yes


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## Large Scale Mark (Apr 11, 2013)

I was able to just put some longer screw in it and looks like will work


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## chuck n (Jan 2, 2008)

Glad it is fixed. It would have helped us help you if you had mentioned that you were using hook and loops.


Chuck


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## Greg Elmassian (Jan 3, 2008)

Funny, we all assumed the knuckle coupler


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## Large Scale Mark (Apr 11, 2013)

Well while I had it down I thought I would grease the gears now it won't run I have messed it up some where


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## chuck n (Jan 2, 2008)

Check to see if the motor switch on the bottom is in the on position. If you are working on the motor blocks it is easy to bump it. Chuck


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## Large Scale Mark (Apr 11, 2013)

The light and everything come on it just won't move


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## Dick413 (Jan 7, 2008)

You did not answer Chuck. The motor switch is a separate switch not with the lights. 
Dick


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## Large Scale Mark (Apr 11, 2013)

I don't have the switches on mine I had a QSI sound system put on it


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## chuck n (Jan 2, 2008)

There should still be switches on the bottom.


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## Large Scale Mark (Apr 11, 2013)

Switches were removed, ok I put on the power ang had a little movement in the front set of wheels but none in the back set


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## Large Scale Mark (Apr 11, 2013)

I think I messed up the gears some how


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## chuck n (Jan 2, 2008)

Mark: 

You are new to MLS. In order for us to help you, you need to provide more information than you think we need. as a group we know a lot about "G" gauge trains, but we are not mind readers. If you review this thread, you will see that we tried to help, but the necessary information came after questions. As to your present problem, do you hear the motor running, what exactly did you do when you lubed the gears? Where do you live, there may be someone here on MLS who live near you who could help you with the problem. We need more info to even start to help. 

Chuck 

PS. It would also help to be able to post pictures of your problems and successes. Posting pictures is very simple if you become a first class member. It can be done if your aren't, but it is easier if you are. It also helps support this site. One that I find very helpful in both directions.

The other day I sent you a PM about posting some pictures of the coupler, but didn't get a reply. Did you get it?


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## Greg Elmassian (Jan 3, 2008)

If you disassembled the motor blocks to lube it, i.e. removed the bottom covers, it's a cinch you have reassembled it wrong. They are very tricky. 

Please confirm if you opened them or not. 

Greg


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## Dick413 (Jan 7, 2008)

Mark if you have your pictures on the internet somewere it is easy to post here, make a reply and then edit and paste. you do not have to be a 
first class member. Also Greg has a lot of this stuff is on his web here is a page about usa 
http://www.elmassian.com/trains/mot...ower#drive 
Dick


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## Large Scale Mark (Apr 11, 2013)

All I did was take the bottom plate off and put grease on the gears some of the gears do move


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## Large Scale Mark (Apr 11, 2013)

I will post picture tomorrow


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## Large Scale Mark (Apr 11, 2013)

I live in Oklahoma City okla


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## Dick413 (Jan 7, 2008)

How to post photos (the easy way) - Non 1st Class Members 

http://www.mylargescale.com/Community/Forums/tabid/56/aff/26/aft/127680/afv/topic/Default.aspx 

Dick


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## Greg Elmassian (Jan 3, 2008)

I assume you meant "gears did move".. Almost certainly they are binding. It's pretty tricky to put them back in place, but you have to basically either remove the motor block completely or you need to "shim" it away from the chassis.

best thing is remove the motor block open up and reassemble with the axles and most importantly the brass bushes in the right way...


If installed wrong you can get either binding, or stripping of the gears. 

Read the paragraph on "drive Problems" on this page: *http://elmassian.com/tra...trong>**

Then read the section on disassembling the trucks on this page: http://elmassian.com/tra...trong>

No offense, but you might need someone more experienced to help you if what you read does not make sense.

Many people cannot get this right.

Regards, Greg

Posted By Large Scale Mark on 14 Sep 2013 06:59 PM 
All I did was take the bottom plate off and put grease on the gears some of the gears do move*


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## Large Scale Mark (Apr 11, 2013)

You are probably right I am going to have to take ang get it fixed right


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## Greg Elmassian (Jan 3, 2008)

It's a very tricky design, so if you want to try yourself, remove the power brick from the sideframes... the sideframes will flex away (carefully) and you can pull the axle tips out of them, this will free the motor block (wires still attached) 

Then you need to read my pages, there are small brass bushings on the axles and they need to go in the right way, that is with a "point" facing up out of the motor block. 

They can be installed wrong, with the flat surface parallel to the top of the motor block, and that will bind the gears, the axle and it's gear will be too close to the other gears. 

You have to "drop" the motor block cover on carefully to not let the buggers move while assembling. The cover should go on with ZERO resistance. 

Also, there is a lot of WRONG information out there on the alignment of the brass bushings (the GP7 and F3 blocks are different) so do follow what I say, it is right (I have a fair number of these locos) 

Regards, Greg


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## Ted Doskaris (Oct 7, 2008)

The following picture may help.

The keep axles from popping out before the motor block lid is removed, you can use a rubber band. 










-Ted


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## Dick413 (Jan 7, 2008)

Nice shots Ted and good idea with the rubber band 
Dick


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## Large Scale Mark (Apr 11, 2013)

Thank for the picture I think this is the problem I will work on this today ang let you know


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