Glenn and Mike,
many thanks for the information! I am fairly new to this so it was very helpful indeed.

Need some clarifications with your replies though, which I hope you could answer.

1) If I have to replace the existing couplers with Atlas or MTL couplers, I would need to buy the coupler mounted Atlas or MTL trucks right  - as there is no other place to fit standalone couplers. Will these trucks fit into the Bachmann freight cars easily?

2) I saw in the Bachmann site itself that they have "dummy knuckle coupler" truck assembly. Can I use these truck assemblies to couple them to the Atlas cars?

Thanks in advance!

The Atlas freight cars (N-scale) seem to be really interesting and I think they have more variety. However, in the pictures I saw on the internet - they have a different kind of coupler than Bachmann.
Would highly appreciate if someone could tell me how to couple the Atlas cars with the Bachmann freight cars I already own? Do I need to replace the Atlas trucks with the coupler mounted trucks of Bachmann or is there some other way?