I have seen that Kadee has three different lengths of couplers. Why is that? Is one length more prototypical than another? What should I use for transition era models? Or does it matter at all?
Thanks, Hansel
Do you run full length passenger cars? What is the radius of your curves? These are the two most important questions.
Kadee offers a wide variety of couplers for different types of cars and locos made by many manufacturers.
Basically, it depends. It depends on several factors including, curve radii, size of car or loco, and whether you want the diaphragms to touch on passenger cars. I will give a great example. I have 9 passenger cars. Currently they are equipped with the standard Kadee No. 5. The diaphragms don’t touch and it looks kind of weird. The reason is that I have too tight of curves. Now when I plan to have a layout with at least 30 inch curnves, then I will change out the couplers for a shorter shank Kadee to make the diaphragms touch.
It is personal choice.
On my N-scale layout I use almost all short shank for close coupling and I do have 16" curves, wide for N. One problem spot I have is on my InterMountain tunnel motors the first car in the train often derails as the coupler mounted in the loco does not allow for enough side to side movement. I have read that instalation of a longer coupler will help rectify this.
Not much but hope it helps.
Kadee makes different lengths (and different head offsets/heights) to fit all the different kinds of rolling stock manufactured over the last fifty years. Most freight cars take a number 5, but locomotives and passenger cars, may need all sorts of things. There is a big “what-fits-what” list on the Kadee website, and in the big Walther’s catalog. When in doubt, I check that list and go with what it recommends.
For most freight applications, the #5, or #58 if you prefer the smaller knuckles, is correct. As has been pointed out, longer couplers will separate the cars more, and may give more clearance if you’re having trouble with long cars on tight curves.
For me, the longer coupler shanks allow me to account for different mounting positions of the coupler boxes. In particular, consider the nose of an F7. There is a pilot housing which is generally molded in plastic at the front of the engine. This puts the frame of the engine a short distance back from the front. So, I need a longer shank on the coupler to reach through the pilot.
Due to the peculiarities of my made-in-Japan rolling stock, my standard coupler is a Kadee 6. The longer shank allows me to use the manufacturer’s mounting hole. A #5 isn’t long enough (coupler head jams on the end sill.)
OTOH, if the car has the NMRA draft gear box, the #5 should be a drop-in installation.
All those other sizes are designed to fit the peculiarities of specific kit and RTR locos and cars. Kadee has a compatability list, but I’ve never had reason to use it.
Chuck (Modeling Central Japan in September, 1964)
As nobody actually answered the OP’s question, I guess I’ll try. Model couplers don’t really relate in that way to prototype couplers. Prototypes are pretty much all the same, with the exception of “cushion cars” with their extended draft gear boxes and rotary dump cars which have rotating couplers.
Models on the other hand may require some adaptation in order to run on our sharper curves and other variations as others have mentioned. Kadee set the standards for knuckle couples with the #5 years ago. All the other variations are designed to allow cars of different heights and lengths to mate up to that #5 standard. To maintain that standard it is a good idea to pick up a Kadee height guage.
modelmaker51 brought up a good point about the compromises necessary to operate on our sharp curves.
i use number 5’s almost exclusively as do most others but if you look at the spacing between the cars you will see it is too great. an HO scale brakeman would have to be pretty long legged to make the hop from running board to running board.
grizlump
For your era, a medium centerset coupler (5, 148, 58, 158) should fill most of your needs. Might need longer couplers on the front of steam engines to clear the pilot . About the only cars with longer shank couplers would be passenger cars.
The pivot point for the coupler is a good 5-6 feet back from the end of the car. The pivot is almost back to the closest axle. Most cast-on draft gear boxes are set up for a no.5, but may not have enough swing on longer cars (70’+). The Walthers swing-arm coupler arrangement seems to help, but can have its own issues of couplers not held in place, too much vertical deflection and/or slop.
Using a long coupler (26, 46, 146, 156) in a Kadee box, set back a bit may work out. The longer coupler has a bit more swing. Set the coupler so that the knuckle is in the right place in relation to the diaphragm, which moves the pivot point back a bit.
I use Kadee no. 5s on all my passenger cars. As shown in my book, The Model Railroader’s Guide to Passenger Equipment & Operation (and my article in the July 2003 MR), I set them back considerably (5/16" to 3/8") for realistic close coupling. Note that the right place for the coupler knuckle in relation to the diaphragm is in line with the striker plate, and that the coupled istance between cars should be about 18 scale inches.
Cars with body-mounted no. 5s (and modified Walthers diaphragms) operate reliably on 30" or larger radii, and I don’t like the looks of 80- or 85-foot cars on any smaller radius.
So long,
Andy