Hi jbiggie (A first name would be so much better)
A warm welcome to this forum of Märklin friends.
Here a Märklin fan from Paris, France.
M track is just great but has been produced over a huge period of time (from 1956 to 1999) and there were changes over the years.

In your case, I understand that when crossing turnouts towards the diverging tracks some locos and wagons derail and possibly on the frog (the sort of "V"-shaped grove and at the same level, you have counter-rails to force wheels to stay in the frog's grove. So if this not the case ignore my message

One of 2 things may happen:
- the derailing vehicles are recent and with a larger wheel-spacing than the "traditional" Märklin. Wheel-spacing for recent trains are 14.0 (Märklin) and 14.4 (2 rail-like trains) as measured between wheel flanges.
- the M track switch is old with metal counter-rails that may need some re-adjusting

Old M Track turnout

In this production style, the counter-rails are made of sheet metal. They are fixed by two metal tongues going through the metal ballast and are slightly twisted underneath.
So the solution is to untwist the tongue (so the counter-rail becomes loose). Next hold it a bit further away from the frog (and closer to the rail nearby) and gently twist it back again
Ideally, having one of the wheel sets that is creating problems helps a lot understanding where and why it bumps on the frog

Note: on later M track productions, the counter-rails are a one piece plastic including the frog and on those there is much less that can be done (but usually they don't get out of adjustment

Cheers
Jean

I have forgotten the wheel flange spacing that is ideal for M track...is it 13.8mm?

Unfortunately this solution did not help, they were a bit loose so I tightened them as you indicated. Still locos continue to derail on them. Now I also read something about axle width. Are there different axle widths> Has that anything to do with it?

Jean,


Many thanks. I have a box full of old goods wagons that are behaving badly. I will double check 13.8mm. But all my old coaches are behaving well...I think they are less susceptible to derailing since they have some flexibility!

It might help if I had track that hasn't been trodden on by small feet over the years

Michael

Hi jbiggie
No the Marklin wheel spacing does NOT vary by itself
You may check easily with a caliper or by comparing with a wheel set you is recent and good
Cheers
Jean

Good afternoon Dennis,

My thoughts were also on sticking something on it. You indicated electrical tape. What exactly is that, I have electrical tape but you mean something else?

Dennis, the translation for this went wrong, I mean I have electrical wire, which is round. What do you mean by electrical tape, flat wire or something like that? Anyway I'm going to experiment with it.

Hi
May I slightly disagree with you?
Electrical tape is very soft and elastic and does not remain in place.
Next, I have used a thin rectangle of brass (bronze is also OK): It is thin, rather hard and allows wheel flanges to glide on it. Big drawback: If it become loose then you get yourself a nice short circuit.

Sorry to repeat myself: The last try I did worked EVERY TIME
- Loosen the metal counter rail.
- Then determine, using a good wheelset the wished position of the counterrail.
- Then attach firmly the counter rail in the exact desired position (keep holding it while you twist the tongue!) by twisting back the tongues under the metal ballast.

The counter rail stays in place exactly where you want and allows a very smooth ride on the turnout.

Cheers
Jean

Yes, you can disagree with me 😊.

As I said initially: it didn’t stay in place!

But it helped me to confirm the problem is solved if the counter rail is extended.

Thanks for repeating yourself … it gave me the opportunity to read your explanation more carefully. I have one question: by following your steps, is it actually possible to attach the counter rails in a slightly different position?

I didn’t attempt this approach because I was not clear if they could be moved. Also, I always avoid twisting the tongues because I am afraid I will not be able to keep them tight and firm later.

Anyway I will get one of my old turnouts and play with it. Thanks!

Denis

I have had one mtrack curved point where this happened regularly with certain stock. Sure enough the counter rail (we call them check rails in the UK) was loose. I didn't want to lift the point so I just held the check rail where I thought it should be and put a couple of dabs of superglue down where the tabs were.
It works well and nothing derails on it now.

Hello
Here is another possibility for derailment on a m track switch. If the tongue doesn’t close all the way it can cause derailments as well. It happened to me but only with a few cars and some tenders. It took me a while to figure out what was the cause for it and found that on 1 switch the tongue was slightly bend and was easy to fix with bending it back into place. Another switch had a worn out spring and needed to be replaced. Hope this helps.

Robert

superglue

I first fixed the counter rail this morning by twisting tighter. That didn't help enough, there wasn't really room to move them a little closer to the rail either. They seemed to be stuck in some kind of frame of hard cardboard or something. Now I used super glue to glue a narrow strip of less than 2 mm from an old bank card to the counter rail, that seems to work. What that means in the long run remains to be seen

This is interessting. I need to do something like this too.
Would it be possible for you to document this more precisely with photos and/or drawings, for permanent conservation of this solution in the forum?