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Engine running backwards....

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Engine running backwards....
Posted by cplmckenzie on Thursday, September 3, 2015 10:14 AM

Hello again,

I'm back with a question on my second ebay purchase.

I got a Life Like HO AHM Penn Central #5050 FM Diesel Powered Locomotive Engine and it is running backwards.

When the pwr sply knob is if forward, it goes in reverse - reverse it goes forward and in relation to the other engines on the same track.

I removed the shell and saw that there were 2 wires (red/white) coming from the motor to the front wheels.

If I just switched those wires around, wouldn't it run correct then?

Thanks (again),

cplmckenzie

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Posted by G Paine on Friday, September 4, 2015 9:03 AM
I assume you are running DC, not DCC. Switching the wires should work.

George In Midcoast Maine, 'bout halfway up the Rockland branch 

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Posted by Steven Otte on Friday, September 4, 2015 9:08 AM

Switching the wires shouldn't be necessary. Under DC control, "forward" and "reverse" are relative to the track, not the way the locomotive is facing. If you turn the engine around, you'd find it runs the "right way." Likewise, if you switch the wires, next time you turn the engine around you'd find it running "backward" again. Just think of that little switch on your power pack as "this way" and "the other" instead of "forward" and "reverse" and you'll do fine. Big Smile

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Posted by E-L man tom on Friday, September 4, 2015 9:15 AM

Actually, you do need to switch the wires - - but not "under the hood" of your locomotive. You need to switch the wires on the terminals on your power pack.

Tom Modeling the free-lanced Toledo Erie Central switching layout.
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Posted by floridaflyer on Friday, September 4, 2015 9:30 AM

Believe the important point is that the if the loco in question moves to the right while all other locos on the track move to the left, or vice-versa, then the loco in question is miswired. If all locos move in the same direction then, as suggested, turning the loco in question around would fix things.   

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Posted by dstarr on Friday, September 4, 2015 9:40 AM

Actually, there is an NMRA standard on direction.  It reads something like with the left hand rail positive and the right hand rail negative the locomotive shall move forward.  If you really care, you can find the NMRA standard at the NMRA website, read it very carefully and check things out.  The standard only becomes important when you are doing things like running an ABBA consist of hood diesels, all units powered, and you really do need all four locomotives to move in the same direction.  If the B units try to go one way and the A units the other, nothing good will happen. 

   HO manufacturers are pretty good about getting electrical polarity and direction of motion right, I've never had a factory locomotive run backward. I would be reluctant to go about switching motor wires inside the locomotive  unless I was VERY sure I had it right.   As long as you are only running a single locomotive, you can make the locomotive's notion of forward and reverse match the legends on your power pack by either switching the wires between track and power pack, or simply placing the locomotive on the track facing in the opposite direction.  Once you are double heading locomotives, as long as they all run in the same direction, you are good. 

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Posted by rrinker on Friday, September 4, 2015 10:26 AM

If this loco is different from your others, switch the wires in the loco. If ALL locos run the opposite way the direction switch is labeled, reverse the wires at the power pack.

                   --Randy


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Posted by Antoine L. on Friday, September 4, 2015 10:33 AM

I have the same problem with a S2 switcher from proto 2k. 

Fact is: switching wires on the powerpack is just like switching the direction switch, problem stays. So, not being good at opening delicate locomotive shells I just use my switcher alone, while no other trains are running on other blocks. DC speaking, of course.

 

Antoine

 

 

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Posted by ndbprr on Friday, September 4, 2015 10:54 AM
If an Ernst transmission was added in some cases there is one more gear Which also reverses direction. Had this problem on Athearn switchers.
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Posted by doctorwayne on Friday, September 4, 2015 11:00 AM

If you have other locomotives and they all run the way that you think they should, then your latest acquisition needs to have the wires switched.
I worked on a brass steam locomotive for a friend, adding all-wheel pick-up, and while it was wired backwards to the NMRA standards, it still ran the same as all of my own locomotives.  As work progressed, I discovered that a previous owner must have had the drivers out of the frame and re-assembled them flipped left-to-right.  Then, as a simpler fix than re-doing it right, they simply turned the tender trucks and moved the wire on the motor to the other brush.

When I took it apart to rectify the situation, I discovered the probable reason for the original disassembly:  most of the driver tires were loose on their wheels.  The flipping wouldn't have cured the problem, so I suspect that it was simply a quick re-assembly to get it somewhat saleable.  Fortunately, since the all-wheel pick-up puts wipers on the driver tires, it caused no problems to use ca to affix the tires to the wheels, even though it makes both sides of the tires insulated from the frame.

Wayne

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Posted by BroadwayLion on Friday, September 4, 2015 11:03 AM

dstarr
Actually, there is an NMRA standard on direction. It reads something like with the left hand rail positive and the right hand rail negative the locomotive shall move forward. If you really care, you can find the NMRA standard at the NMRA website, read it very carefully and check things out. The standard only becomes important when you are doing things like running an ABBA consist of hood diesels, all units powered, and you really do need all four locomotives to move in the same direction. If the B units try to go one way and the A units the other, nothing good will happen.

There is a standard, but I think you have it backwards.

LION puts GROUND on the left rail, and positive on the right rail, the train goes forward.

ROAR

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Here there be cats.                                LIONS with CAMERAS

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Posted by BroadwayLion on Friday, September 4, 2015 11:08 AM

doctorwayne
If you have other locomotives and they all run the way that you think they should, then your latest acquisition needs to have the wires switched.

Atheran locomotives used to be Truck Sensitive. If you switched the trucks fore and aft, then the locomotives would run in the opposite direcdtion.

TAKE A LOOK AT THE LOCOMOTIVE.... Find the F on the frame of the locomotive. THAT is the Front. Sometimes the front of the locomotive is not where you think it is. Some roads run locomotives long hood forward, others the short hood forward.

Thus trains should not run in the same direction if you have them pointed the same way.

ROAR

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Posted by jjdamnit on Friday, September 4, 2015 12:34 PM

Hello All,

The engine in question appears to be an F unit possibly an E unit.

As Steve Otte said "forward" and "reverse" are relative terms.

I'm thinking you want all of your locos facing in the same direction to all move in that relative direction.

When I ran DC I setup the track polarity to match the position of the switch on the power pack with the direction of travel.

If the direction switch was to the left (<) I wanted the trains to move from right TO left <<<<. If the switch was to the right (>) I wanted the trains to run from left TO right >>>.

To change the overall direction relative to the direction switch on the power pack, switch the wires feeding the track.

From what you're describing when the direction switch is in one position the locomotive you just purchased runs opposite to relative to the others when facing in the same direction.

In my last post to you I talked about consisting. With F units it was prototypical to run the lead unit "forward" and the second unit "backwards." When the train arrived at it's final destination this tail to tail configuration meant that the crew simply switched to the unit facing in the other direction and that became the lead unit without having to physically turn the engines around with a turntable.

I suspect that the previous owner might have wired this loco for this type of MU'd operation by either switching trucks front-to-back or re-soldering the motor connections.

If it was manufactured overseas the polarity might not have been wired to the NMRA standard.

Who Knows???

Once you have determined which way is "forward" on your pike (mine is clockwise) set up the track polarity so that the direction switch represents this with the bulk of your locomotives.

If you have any that run "backward" relative to the others this is the one you'll need to switch polarity on the motor; white to red and red to white, in your case.

With some types of diesel locomotives "forward" was determined by the railroad itself.

The same locomotive for one railroad might have been run with the long hood forward and one might have run the exact same loco short hood forward.

This question was addressed in the following forums:

http://cs.trains.com/mrr/f/13/t/246925.aspx

http://cs.trains.com/mrr/f/13/t/245561.aspx

Hope this helps.

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Posted by csxns on Friday, September 4, 2015 3:29 PM

BroadwayLion
you switched the trucks fore and aft, then the locomotives would run in the opposite direcdtion.

That i did before without knowing it will happen and you can take the Athearn motor apart and rotate the middle and the same will happen a great way to have a head on if you run DC only.

Russell

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Posted by Darth Santa Fe on Friday, September 4, 2015 3:52 PM

Ah, the AHM C-LINER! I've had plenty of experience with these. If it's running in the opposite direction from anything else you own, switch the two wires on the motor around. They should be soldered to clips, so it's a simple matter of popping them off and switching them.

It looks like the traction tires are missing. If they are, you may want to get some Calumet tires if you want your C-LINER to pull much. https://www.walthers.com/exec/productinfo/192-505

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Posted by dstarr on Friday, September 4, 2015 6:46 PM

Not unlikely.  You have to read the NMRA standard very carefully and make sure you understand what they mean by forward and backward, left hand and right hand, and some other stuff.  And it's still easy to get it wrong.  For myself, until I have units in a consist, running in opposite derections, I would avoid messing with the insides of locomotives.  If all the locomotives in a consist run in the same direction, all is well. 

  I didn't bother to read the NMRA standard befoe posting, I just quoted from memory to give a feel for the issues it addresses. 

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Posted by DSchmitt on Friday, September 4, 2015 7:20 PM

If the engine runs left while all the others run right, the wiring on the loco is switched.  Reversing the wires will fix the problem.  

Is it a used loco? Some model railroaders reverse the wires on a few of their locos because a loco running "backwards" is usefull in their their operations.  

 

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Posted by rrinker on Friday, September 4, 2015 7:59 PM

 The wiring does not have to be reversed to MU in DC. NMRA standard is if the engineer's side (right) rail is positive, the loco runs forward, which with a cab unit is obvious, with a hood unit, look for the F because some railroads run long hood forward and some ran short hood forward, most these days is short hood forward. Then there are the ringers - where the prototype was dual control, so the label on the frame would be F1 and F2. Which one is the Front Front? Pick one.

Now, if you have a loco, say an F unit, and it is facing to the right, and moves forward when the right hand rail is positive, perfect. Now take that loco and pick it up and put it back in the rails facing left. Now the left hand rail, relative to the position of the engineer, is positive, and the loco should run backwards. So to couple a pair of F7 A units back to back, no rewiring is needed.

 That's the way they SHOULD work. Altered gearing, or a motor replacement that was hooked up backwards, or a loco just designed to run the "wrong way" per prototype, will affect this. I never tried one of my P2K Geeps on DC power, but Reading ran them long hood forward. P2K has the F on the end of the long hood, correctly, but with a DCC decoder plugged in in the proper orientation, forward moves them short hood forward (and they have the crew figures facing the short hood!). I suspect that on DC they will do the same, the 'forward' direction will be towards the short hood instead of the long hood. Fixing that simply means reversing the motor wires.

                                --Randy


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Posted by BRAKIE on Saturday, September 5, 2015 2:04 AM

If your other locomotives is running as they should  and the FM isn't then simply reverse the locomotives wire since it is wired backwards.

 

Larry

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Posted by BRAKIE on Saturday, September 5, 2015 2:12 AM

 

Randy, A prototype locomotive will run equally well in either direction when mu'd..Our models will do the same without any unneeded wire change.

A powered set of A units running back to back will mu perfectly.Same for any locomotive consist.

Larry

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Posted by rrinker on Saturday, September 5, 2015 10:43 AM

BRAKIE

 

Randy, A prototype locomotive will run equally well in either direction when mu'd..Our models will do the same without any unneeded wire change.

A powered set of A units running back to back will mu perfectly.Same for any locomotive consist.

 

 I think that's what I said?  Trying to dispel the myth that to MU back to back in DC you have to rewire one loco. Not if they were both wired correctly to start with.

                    --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by cplmckenzie on Saturday, September 5, 2015 11:59 AM

Well, after looking into some of you guys suggestions. I decided not to mess with rewiring the loco in question. I will just use it as my Yard Shifter loco, which needs to run opposite all the others anyway.(running against all spur turnouts for shifting cars to make an outbound train).

I do have another question tho, not related to the last one.

I am sure there is a formula to convert HO scale distance to 'real world' distances.

For instance, if in HO scale the distance is 36" then how far is that in 'real world' footage?

Thanks

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Posted by BRAKIE on Saturday, September 5, 2015 12:20 PM

rrinker
I think that's what I said? Trying to dispel the myth that to MU back to back in DC you have to rewire one loco. Not if they were both wired correctly to start with. --Randy

Randy,So,you did..My humble apologies..Serves me right for answering questions and reading replies in the middle of the night..

Larry

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Posted by rrinker on Saturday, September 5, 2015 12:41 PM

I did go back and re-read what I wrote, since I wrote it in the middle of the night Big Smile 

You never know.

                 --Randy


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Posted by doctorwayne on Saturday, September 5, 2015 12:49 PM

Darth Santa Fe
....It looks like the traction tires are missing. If they are, you may want to get some Calumet tires if you want your C-LINER to pull much.....

An even better solution, and one that would cure the "wrong way" problem, too, would be to scrap the original drive and mount the shell on a Stewart (now Bowser) chassis for a Baldwin AS-16.  It's pretty-much a drop-in fit.  Detail Associates offer the correct press-in C-liner sideframes, too.


Wayne

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Posted by ggnlars on Saturday, September 5, 2015 5:21 PM

I see this a lot.  In DC if you want two trains to meet in opposite directions on the same track, the engines on one have to have reversed polarity.  This can only happen with switched wires.  If you switch the motor leads, all will be normal.

Larry

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So many trains, so little time,

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Posted by BRAKIE on Saturday, September 5, 2015 6:12 PM

ggnlars

I see this a lot.  In DC if you want two trains to meet in opposite directions on the same track, the engines on one have to have reversed polarity.  This can only happen with switched wires.  If you switch the motor leads, all will be normal.

Larry

www.llxlocomotives.com

 

 

Or with Athearn BB locomotives,reverse motor or trucks will do the same.

 

Please don't ask...Embarrassed

Larry

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Summerset Ry.


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Posted by Darth Santa Fe on Sunday, September 6, 2015 12:19 PM

doctorwayne

Nice job on that one! For a moment, I thought it was a Proto 1000 model!Big Smile

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Posted by jjdamnit on Sunday, September 6, 2015 12:52 PM

Hello All,

I use the online conversion calculator on the Garden State Central Model Railroad Club here.

I also purchased several HO scale rulers available online or a your Local Hobby Shop (LHS).

Hope this helps.

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Posted by doctorwayne on Sunday, September 6, 2015 2:26 PM

Darth Santa Fe

Nice job on that one! For a moment, I thought it was a Proto 1000 model!Big Smile

 
Thanks, Darth.  I did that one for a friend, who later acquired some of the Proto ones.  I'm pleased to say that it doesn't look out of place with them, although I'd redo the handrails and grabs on the Protos if they were mine. Smile, Wink & Grin
 
Wayne

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