I have a Bachmann HO train with New Haven couches. I broke one of the couplers and don't know what size couplers to buy. The couplers on it are EZ and ~16mm in length from the head of the coupler to the rear. I think I need BACHMANN EZ MATE CENTER MEDIUM HO COUPLER TRAIN 78025 but am not sure. Can anyone help me??
I think you mean "coaches," I don't think you meant "sofas" or "davenports," but if I recall they had medium shank couplers included. If you are running on tighter radius curves, you'll want longer couplers, although less prototypical, they allow for better running on tight curves. Shorter couplers are more prototyical looking, but don't work out as well on 18" radius curves, but if you have 24" radius or larger, it doesn't matter which ones you use.