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??