Problem with S-Curve

The tight space requires a lot of curves, and there is at least one S-curve in the layout. Due to the arrangement of the couplings between cars, there is a problem: a right-curve, followed by a left-curve, results often in a de-coupling between cars. This happens only if the cars are a certain size or longer: this is because then the offset due to the two curves is too large to keep the cars connected.

What helps:

• increase the curve radii, so that the coupling offset gets smaller. But there are tight space constraints.
• use only small cars. This limits of course the usability of the track.
• add a short straight section between the two curves. This could be done, but depends on space constraints.
• remove the left-right S-curve and re-plan the whole layout so that instead a right-left S-curve is there.

The latter one has its reason in the side-ways coupling of the cars, which is not symmetrical. In a right-left S-curve there is less stress on the coupling, and the cars remain connected. 

Using shorter cars:

Ultimately I decided to redo the whole layout and replace the tight right-left S-curve with a tight left-right-S-curve. This did for now solve the problem. The newly created right-left S-curve at the top level was "straightened" by inserting a longer straight part.