620/720 couplers

 
  prewett Junior Train Controller

Location: Albury, NSW
I have a problem with the Eureka 620/720 couplers when the power car is pushing the unpowered on curves, 1 metre diameter, it derails.

I think it is because the ends are touching, I have extended the couplers by adding a short brass strip but this has not worked.

Does anyone have a suggestion on how to modify?

Have thought Kadees but mounting is not the easy or a solid strip with pivot in the middle.

Peter

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  Roachie Chief Commissioner

Location: Kadina SA (formerly NSW)
I have a problem with the Eureka 620/720 couplers when the power car is pushing the unpowered on curves, 1 metre diameter, it derails.

I think it is because the ends are touching, I have extended the couplers by adding a short brass strip but this has not worked.

Does anyone have a suggestion on how to modify?

Have thought Kadees but mounting is not the easy or a solid strip with pivot in the middle.

Peter
prewett
G'day Peter,

I don't own a Eureka 620/720, however I have a couple of observations/suggestions for you.

1). Have you tried using a different loco to push the unpowered car over the same section of track?...or even push the car by hand? If this works okay, then that eliminates one possible problem. However, if the car still derails, then we can safely say that the problem probably lies within the unpowered unit.

2). Do the bogies of the U/Powered car swing freely enough such that they are not being forced to de-rail by virtue of them snagging on the "skirts" of the super-structure?

3). Do the bogies, when being turned on their pivot/s, remain horizontal? By that, I mean is there any distortion in the angle of the bogie in relation to the remainder of the car, as the bogie pivots on it's centre point?

4). Have you tried temporarily adding some extra weight (on the roof would do) as an experiment? It may just be a case of needing to add a small amount of weight over one/both bogies to avoid the U/Powered car from jumping the rails.

5). Does the de-railing only happen on one part of the layout? It could be that there is a slight "hole" in the road and the bogie/s do not have enough lateral play to enable it/them to conform to the irregularity. You may be able to back-off the pivot screws in the centre of the bogie/s, to enable them to ride over such irregularities with de-railing.

See how you go with some/all of those ideas.

Cheers

Bill Roach
  prewett Junior Train Controller

Location: Albury, NSW
The problem is that there is slack in the coupler, even when new the spacing between was very tight, now they are touching even on a straight section.

Thanks for suggestions.

Peter
  Roachie Chief Commissioner

Location: Kadina SA (formerly NSW)
The problem is that there is slack in the coupler, even when new the spacing between was very tight, now they are touching even on a straight section.

Thanks for suggestions.

Peter
prewett
You could replace one/both of the couplers with a longer shank type, that would get them a bit further apart.

Yell out if you need one as I have several.

Cheers,

Bill
  prewett Junior Train Controller

Location: Albury, NSW
They are not Kadees or normal couplers but fabricated as part of the body with a moving plate sticking out with a hole and (to short) pin respectively, they have a spring to hold in centre and when going around corners the plates extends so that cars is moved further away.

There is limited space to fit a kadee box.

Trailing car is wired to power car via two connectors which limits space even more they are designed to run in pairs only so do not need the decoupler.

What I was hoping for is to see if others have modified the coupling method.

Thanks,

Peter
  Bowen_Creek Station Master

Hi Peter

I have noted the same issue, I haven't done anything about it yet but I had an idea of replacing the coupler with a solid bar.
I generally think there are too many pivot points on the existing one causing it to lock and lift the lighter unit. With a solid bar it would reduce these points from 3 to 2. Just a thought that maybe worth a try.

Andrew
  prewett Junior Train Controller

Location: Albury, NSW
I have contacted Eureka but no help - disappointing.

I thought they may have had a fitting that could be used as they know there is a problem with the couplers.

There does seem to be a lot of vertical 'slop' in the couplers that is not helping.

Peter
  M636C Minister for Railways

I have contacted Eureka but no help - disappointing.

I thought they may have had a fitting that could be used as they know there is a problem with the couplers.

There does seem to be a lot of vertical 'slop' in the couplers that is not helping.

Peter
prewett

I found the same problem when trying to demonstrate the cars on Bachmann 18" radius curves away from home.

They run quite reasonably on larger radii but they are not designed to run on curves of less than about 24" radius (610mm).

I found that by running them with the couplers uncoupled with the power car pushing, the connecting cable was enough to keep the trailer a reasonable distance away and the train could be run.

The real answer is to use larger radii.

It's a while since I've looked at them but could you make an intermediate link between the couplers to hold them further apart. Perhaps from a paper clip or similar?

M636C
  prewett Junior Train Controller

Location: Albury, NSW
I had tried installing a small brass plate which extends the coupler length by 5mm this does not work, probably to much play/slop.

Perhaps putting wheels on with a larger flange will stop it derailing!!

Peter
  Black Hoppers Chief Train Controller

Location: Banned
I had tried installing a small brass plate which extends the coupler length by 5mm this does not work, probably to much play/slop.

Perhaps putting wheels on with a larger flange will stop it derailing!!

Peter
"prewett"

You could allways add weight to the dummy car.
  Roachie Chief Commissioner

Location: Kadina SA (formerly NSW)
I had tried installing a small brass plate which extends the coupler length by 5mm this does not work, probably to much play/slop.

Perhaps putting wheels on with a larger flange will stop it derailing!!

Peter
prewett
Peter,

I'm still grappling with exactly what arrangements this set has as standard....but it seems from what I have read that there is a double joint; meaning 3 pivot points. If this is true, then I would suggest you fabricate a "stiff bar" that is screwed to each carriage in such a way that it (ie: the bar) can still pivot on each car, but removes the extra joint between them. This would be identical to the system employed on the vast majority of steam locos between loco and tender.....and we rarely hear of any endemic failures of the tender (ie: the unpowered carriage if you like) derailing when a steam loco reverses.....and they can often be pushing a substantial load in the form a train!

Cheers

Roachie
  David Peters Dr Beeching

Location: "With Hey Boy".
Black Hoppers might be on to something here a little more weight over or as near to the bogies as you can get might make it better, and Roachies idea about a solid draw bar is also worth trying, it might take both these idea's to cure it. You can only try.
  prewett Junior Train Controller

Location: Albury, NSW
The coupler is a complicated system in that it is designed when going around a bend to extend the distance between cars .

There is triangle shape piece in a hole in the frame and the coupler is held against the top of the angle by a small spring and on a corner the coupler slides down the edge of the wedge moving it closer to the end of the car.

The hole takes up a lot of space and fitting a solid bar is not easy as bogie hole is close to that of the couplers which has a connector for cables either side there just no space to install an alternative. It would mean taking out the bogies (including powered ones) and dismantling the unit completely, not an easy job having had the unit apart I could not see how to take out the powered bogies or even to service the power drive as totally enclosed.

It would need a long U shape bar to be screwed in place beyond the bogies if not dismantling.

One idea was to do away with the extending ability and fix the coupler in place permanently and by using the small brass extension that I installed keep them seperated.

Thanks again for suggestions.

Peter

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