Have you checked whether the buffers overlap with the loco or the next coach?

Long Marklin coaches usually have adjustable buffers. Push them all the way in if you are using sharp curves.

Andreas,

the models you refer to are 2 bogie (4 axle) SNCB local/commuter coaches, similar to the SBB lightsteel coaches in many ways. These coaches do not have adjustable buffers, so we can discount this as a solution. It is possible that the buffers or gangway are forcing the coach to tip if they are rubbing in a curve. You should check to see that the gangway pieces (baffles) are corrected installed on the coach ends and do not rub in a curve. One way to test this would be to replace the Maerklin close coupler on the middle coach with a normal coupler (traditional Maerklin type) or even a Roco Universal closecoupler, both of which will add a mm or two to the spacing between coaches and between the coach and the lok.
You mention that the coach seems prone to tilting even when run alone. The bogies clip into the bottom of the chassis. Make sure that the bogies are correctly in place and that all axles are sitting properly in place. As far as I remember, this model does not have any clips on the axle shaft. As the axles are isolated, you can pop them out and reinstall them and see whether this improves performance. Also make sure that the coupler is not bent and rubbing against the buffer of the lok or other coach in a curve or switch. You should also check to ensure that the close coupling shaft is not interfering with the rotation of the bogie.

The coach should not tilt more than the 43534 or 43536. You should be able to compare this on a flat surface or straight track by observing how much the coaches lean to the sides when you tip them with a finger while keeping it on the track.

You did not specify what radii you are using. The coaches are designed to be operated on all Maerklin radii.

I suspect that the drag from the coach behind it with built in slider may be too much for the middle coach to handle. This can happen on tight radii as due to the resistance, the middle coach becomes the weak point and derails. In such a case, there is force exerted not only along the direction of the tracks, but the locomotive also exerts pressure on the trailing coach towards the lok (cutting across the radius of the curve). You may wish to check the 53536 to make sure it is not creating any additional drag on the middle coach. Try replacing the 43536 with another 4 axle passenger coach and see if the 43532 continues to have the same issue.

I have a few more diagnostic questions. If you place the lok and coaches in the other direction and invert the 43532 so that the bogies are turning the opposite direction, does the problem still occur? What about when the pilot coach is in the front?
I was able to detect a similar issue with the Swiss lightsteel coaches by observing the problematic coach carefully while moving at slow speed. In that case, the gangway piece was being blocked by the clear window pane piece which had been mistakenly factory installed in an inverted manner, which would not allow the gangway piece to be fully inserted into the coach body. As you stated that the problem did not occur when you first acquired the models, this is not likely the same situation. I would however suggest that closely observing the coach will lead you to the first symptom of the problem, which may lead to a solution if you can see what it causing the coach to lean.

I hope that this helps point you in the right direction.

Regards

Mike C

Gangway = the passage alongside the compartments in a train coach and the passageway between two coaches using a set of baffles.

I realize that for a non-English speaker, some of these terms must be baffling (confusing).

I think I know what you are referring to on the coupler. That little piece should not affect operation in normal circumstances. You mention the generator (simulated) which is attached to one side of the bogie. That should not cause any problems unless it is pushing up against the coach body in a curve.

Look to see if there is anything that is pushing down on the bogie (or coupling) or up against the coach body when the bogies are curved. If something is causing the coach to tip, this could be the cause of the frequent derailments.

If you can take a photo with a digital camera or cell phone, you can post it in the forum here: https://www.marklin-user...s/upload/uploadstart.asp

Once you have uploaded the photo, copy the link and post it in your message using [img] paste address here [/img]

Regards

Mike C

Mike c and HO thanks again for your help.

This morning I changed the orientation of the problematic car, and there was no problem. So whatever the reason for the derailing was, it was fixed after the actions described in my previous message.

I am under the impression that the yellow rectangles have nothing to do with the first class yellow line seen on most 1st class cars as well as this one. At least this is what I think, I may be wrong.

The rectangles can be seen below:



If anyone knows what they mean, please be kind enough to share the information, I would be most grateful.

Thank you all so much for all your valuable help.

Best regards - Andreas

I have also had problems with couplers causing derailments. I use M track and the 5100 (180 degree) curve is the area where derailments sometimes happens. The 5120's also cause problems on freight cars.

The two locs involved are the 39300 and 39302 (both really nice) and the cars involved have been the 41928 (Reingold passenger cars). I tested this and my conclusion is the bumper - coupler are too close (vertically). The bumper on the loc crosses over the coupler (this action always occurs and is okay) but will sometimes press down on the coupler and cause derailment. I removed the bummpers of the loc and no problem. However, loc doesn't look nice without the bumper. Same happens with freight car 46528. only run the passenger cars on 5100 and 5200 curves and this issue only occurred on some 5100 sections.

My solution with the passenger car is to use an older loc 3058. No problems.

I also encounter this problems in set 46542. Here, one particular car of the set coupled with the next car differently. It seems all the cars couple with the trailing coupler feeding under the leading coupler (or other way around). However, this car is different. Again, the bumper would cross over the couplers on the 5120 and on this one connection, it would press down on the coupler. Same issue like the loc. Again, the crossing over occurs on all connections when on a 5100 or 5120 but the 'sriking' is unique. It seems to be an issue of mm's. I experimented in setting up the order of the cars and 'forcing' the fit. It now works but I have to remember not to decouple the back cars of this 6 car set.

Harvey

In case of modern coaches with the 7203 close coupler, replacing the coupler on the first coach with the traditional Maerklin coupling increases the spacing and will allow for safe operation. You can also try the Roco Universal Close Coupling and see if this provides a better response.

For older models with metal couplings and coupling shafts, it is possible that the couplings or shafts may be bent or out of alignment. Maerklin used to make a tool for measuring the coupling height. Keeping the couplings at the correct height is important for safe operation.

Regards

Mike C

Harvey,

72060 is the correct part number for the Relex coupling with the NEM connector. Instead of using these, I usually use the ones that came with Roco cars and coaches that I have converted to 7203 or Roco Universal Close Coupler.

Regards

Mike C