Different couplers are getting undon all the time on both trains. Track is nice and smooth.

Please help i am new at this hobby and need help I just layouted a nice track plan and with a little help it came out real nice. i am running two trains on two the different tracks and my main problem is the ez mate couplers for both train are always undoing it is driving me crazy ever other turn the couplers are coming undone. I replaced a couple of couplers but nothing has changed could someone please offer some advise as to help me.. thank you Joe

My trains are DCC thanks for all your help guys....

Can someone please help me I am new to model railroading i am in the process of making a layout with three separate ovals which have a few remote turnouts can which do not connect to each other. Do I have to use threee separte power packs or can I buy and use Digital comand control system thanks. p.s. also i have two brand new trains that I am running on a track very slow going Is  this because of a cheap power pack and if I buy the DCC will this help improve the speed thank You Joe...

Thanks Johatan for your help. i appreciate joe...

Can someone please tell me what kind of couplers would I use on the bachmann item no.01314 cavalier train  set. thanks joe