Coupling height for 009

[Hobby]

decided to use an intermediary flat car to couple my
mismatched rolling stock.

The key is simple, use one "gauge", whatever it might be, and stick with it.

[Hugh Norwood]

I'm going to be heretical here and suggest that if you are not going to be doing any hands-free (un)coupling, then so long as all you stock stays coupled up, you do not have to set all your couplings to the exact same height.

[B.Meldon]

I'm going to be heretical here and suggest that if you are not going to be doing any hands-free (un)coupling, then so long as all you stock stays coupled up, you do not have to set all your couplings to the exact same height.

There is more to it than that.
If the loop is too low it will hit on the vertical part of the next coupling and not lift up and not couple up.
The loop has to hit the part of the pin that is sloping to lift up.
This is quite common on the new minitrains locos where the couplings on the loco are set too high for the loops even on the minitrains rolling stock.

There is also more to it than just the height as well.
For example, the Peco GR-101 009 couplings have too long a distance between the front face of the coupling and the back edge of the pin for other makes of coupling loops to get over. These have to be modified by filling down the front face or the back edge of the pin.
This may not be obvious using a coupling height gauge, but it is when using a complete coupling on a wagon as a height guide.

Brian Meldon