I came across a box of height gauges that are very nice to have and use. Check coupler height right on your track and no short. You will know right away if your coupler is correct or not. We use them at my O Scale club and they work great on the DCC layout. I had to buy the entire box so I am selling the excess for what I paid.
$25.00 each plus shipping.
If interested, let me know, thanks!