Will Sergent Engineering Couplers mate with conventional HO scale dummy couplers?
Sometimes. Most (but not all) dummy couplers are designed using the profile defined by the NMRA’s RP-21.1 issued in 1957. This contour is about 25% larger than an actual scaled down version of the prototype. A little creative work with a file can usually result in a dummy knuckle that will reliably mate with the prototype contour used by the Sergent Engineering Couplers. The Glatzl dummy couplers offered by Sergent Engineering do however mate with Sergent Engineering’s operational couplers with no modifications.
