Let’s Talk about Coupler Height in American OO
A question came in about coupler height, how I arrived at my coupler height, and what the standards might actually be.
Looking back in this site, I wrote about this topic briefly in 2009, as follows:
Get coupler height just right
Coupler height is critical. My “height gauge” for years has been the rear coupler on this locomotive. It sits on the test track right above my workbench. It, along with the NMRA standards gauge, is an indispensable tool. I get everything to be essentially exactly the height of this coupler. This prevents many problems.
How did I arrive at this height?
As much as anything I initially matched the height on what looked like a correctly set up Scale-Craft car and then stuck with it. That height seemed close to the height other models “wanted” to be at.
To that locomotive rear coupler specifically, a standard No. 5 Kadee coupler is sitting in the standard box on the “shelf” created by cutting out the HO coupler. As it was a small, handy model, I used that coupler as my standard height.
Any confirmation?
This article got stalled for a while, as I feel sure that I have a piece of track with a coupler height gauge mounted on it. But I’ve come to the conclusion I must have given it away, likely because it matched my standard height so closely. It was from an “OOldtimer.” If I find it I’ll update this article. But I was encouraged to see that it was the same as my standard height.
The Scale-Craft standard
I’ll also go back again to the idea that a standard Scale-Craft freight car, all original in good shape with one standard Scale-Craft washer per truck, is the same height as my “height gauge.” Especially the stock car and original boxcar (with the “flat floor”), they simply have to be a certain height that is high enough that the wheels don’t rub on the bottom of the car – and they don’t look good if they are set much higher than just clearing the frame well. That height, to my mind, is the practical standard for us today.
But in the end, in terms of operations, you just need to be consistent. Good luck!
Hi John, I mounted an MK 5 HO coupler on a SC tankcar (1 washer) and the “Rough” measurement sitting on the table without a gauge was 11.5 mm on one end and 12 mm on the other. NMRA Standard is 11.5, so it was about right. My OO is for display on my OOn30 module, (OO Scale on HOn3 track) but I try to model accuratly as can. Info is quite scare in OO, so I appreciate your articles! Thanks Rob H