i was running trains yesterday and realized a few of my couplers are a tad uneven so when i reach the industrial part of my layout the couplers move downward and come loose is there a way to make the couplers stay high enough without useing a coupler height gauge
why would you not want to use a coupler height guage? they aren't expensive and will save you a world of frustration. this is a must have tool for any serious model railroader. not only will this guage tell you if your coupler height needs adjusted, it will also give you an idea of how much adjustment, and tell you if your trip pins are too low. all of these will affect how well your couplers perform.
I agree with what Jeff said and also, you may have too sharp of a transition in your trackwork heights which causes the couplers to come unhooked. You must allow for a gentle curve or else this will occur.
my track is completely even i think its the cars and the couplers at the most
If it always happens at the same spot as your post implies you likely have a low and or high spot otherwise your couplers should not be movong up and down on their own, you may need to shim your track.
if you dead set against buying a coupler gauge, use the coupler on one locomotive on a section of straight level track to set all your couplers to the same height.
NM
i have had New cars where sometimes the coupler higher or lower than the rest of the cars.
For whatever reason, sometimes the coupler pockets are just a bit too high or a bit too low.
These can help:
Kadee Overset and Underset.
http://www.kadee.com/htmbord/HO-Scale%20Couplers.htm
just pick what will solve your problem.