Large Scale Coupler Basics

Most Large Scale manufacturers use their own proprietary knuckle couplers or hook and loop couplers. As many modelers have found out, some may or may not be compatible with each other both operationally and coupler mounting heights. Kadee® couplers, when installed correctly and using our Delayed Magne-Matic® Uncoupling system, are a complete "hands off" coupler system. Kadee® couplers can be fitted to almost any model which eliminates any compatibility issues.

Our large scale couplers represents the common Type E coupler and come in two types and two scale sizes "G" scale 1:22.5 and #1 scale 1:32 scale ratio. Our original coupler style has an exposed knuckle spring with minimal details. Our newer style AAR Type E (New Generation) has a much more prototypically detailed coupler head and the knuckle spring is hidden inside the head and cannot be seen. Both styles are completely compatible with each other and use the same draft gear boxes, so the conversion information is the same for both.

Kadee® coupler heights are based on the NMRA Standards S-1. For large scale the G-Scale 1:22.5 couplers are the most popular couplers. The coupler height is 1 1/8" (1.125") and #1 scale is 1 1/16" (1.0625" or 27 mm), measured from the top of the rails to the "center" of the coupler head. These heights are very close to the correct prototypical coupler height that is in line with the center beam of a freight car. On some models we have to use an off-set coupler to raise the coupler to the correct height especially on truck mounted coupler arms. Many large scale manufacturers use truck mounted couplers on their rolling stock for a number of reasons mostly to be able to negotiate tight curves and to mount their proprietary couplers low enough to use their in track uncoupling devices. This low mounting height means that to put a Kadee® coupler on the original truck mounting we have to use a large off-set coupler that "goose necks" up to the correct height. We offer large and medium off-set couplers, as well as center-set couplers to help achieve the correct coupler height.

Since "Large Scale" covers several different actual "scale proportions" ranging through but not limited to 1:32, 1:29, 1:24, 1:22.5, and 1:20.3 scale ratios. The choice of what coupler size to use is left up to the modeler. Some like the smaller #1 scale (1:32 scale) couplers because of their more to scale appearance on 1:32 and 1:29 scale models. You usually have to use 1:32 scale couplers on #1 scale models regardless. But on other scale models you have a choice of either #1 or G-Scale couplers. G-Scale couplers are the most popular couplers used in Large Scale.