New cars normally are equiped with a coupler pocket and kinematics. Thanks to the coupler pocket changing couplers has become quite easy. Some manfufacturers even standartly equip their cars with a close coupler, others a classical loop-and-hook coupler. I set no great store on close couplers tor freight trains; but for passenger trains I prefer this, if possible.

So, this description mainly deals with four-axled passenger cars.

I posess several old stuff without any NEM coupler pocket, so I had to take a close coupler compatible to normal loop-and-hook couplers. My first idea was the Märklin close coupler. Märklin cars are standartly equiped with Märkllin short coupler so it would be the easiest way to equip other manufacturers' cars with that coupler, too. However the tests dissapointed me. In curves, the couplers' loops interlocked the puffers. The reason why Märklin cars don't make any problems with that coupler: Märklin's puffers are a little bit too high, so the couplers have enough liberty of action.

Also copuling a Märklin car with close couplers with a Roco car with classical Roco loop-and-hook couplers caused problems i.e. derailments in curves. This meant I couldn't operate trainsets consisting of Märklin ans Roco (or other manufacturers') cars - so I had to look for another solution.

Roco's "Universal Coupler" is also a close coupler compatible with normal loop-and-hook couplers. I choosed this coupler and equiped several Roco and Fleischmann cars with it. I made several test runs and was very lucky with the result - everything worked well. First I had some doubts if the cars would uncouple from locomotives with loop-and-hook couplers in curves, because the coupler's hook is open on the right side - but nothing like this happened.

So, there was only one remaining question: must I also equip my Märklin cars with the Roco coupler? I added Märklin cars (which are equiped with a Märklin close coupler) to the test train - once again good news, everything was working well. So, I finally had found an answer to my "coupler question":

1. Märklin cars keep their original Märklin close couplers.

2. Some Fleischmann cars also run with Märklin close couplers. Simply test it out. If it works, you can use the close couplers of Märklin freight cars, the freight cars get loop-and-hook couplers then. If it doesn't work, use Roco universal coupler. .

3. All other cars get Roco universal couplers.

Meanwhile, I'm running mixed trainsets consisting of Fleischmann, Liliput, Märklin and Roco cars on my layout - without any derrailments and good driving charackteristics.