Originally these cars probably used link and pin, but were possibly converted to knuckle couplers later. Lacking extended striking plates, they are best judged at end sills. Since spacing increased over the years, the era selected will determine the optimum spacing. If they are mixed with older IHC or Mantua cars, closer spacing should be used, along with removal of stikers and addition of dead blocks. Apparently, later in the 70's, dead blocks slowly disappeared and some cars had endplates resembling strikers. If operating with cars of the knuckle era, wider spacing is suggested.
First the car must be measured for setting up CAD. Truck center distance (Tk-TK) = 3.129". Striker to truck center (ST-TK) = .859". Half endsill width =.639". Half striker width = .129". Striker to endsill = .0445".
USING CAD DRAWINGS a thorough evaluation is made.
Found from Measuring Couplers, the 711 pulling face to stud rear = .406". The mounting hole = .107" The pulling face to mounting center with this box is .406 - .057 = .483". For coupler relationships see KADEE 711 EVALUATION.
For link and pin, the PF-ES = .09875" is used. The heavy line is the end sill reference and the solid line to the right is the striking plate extension, which will be removed when adding deadblocks.
Based on prototype data, at the bottom dashed in is endsill to the left and the far right dashed line is the link mid-point at 8 3/4" from the endsill for 17 1/2" separation. Note that this is the center position with no pull, where spring presses shank against post.
Note: Adjust brightness and contrast for optimum viewing.
NO PULL WITH 17.2" SPACING
The PF-ES = .09875 = 8.602" for ES-ES = 17.204". ES-MC = .246" for locating mounting center.
In the maximum pulling position, the spring will compress. In this case the rear of the shank hole will be against the post, yielding about 19.73" ES-ES.
During pushing, the knuckle slack reduces distance greatly.
MINIMUM RADIUS CHECK
With their short wheel bases, these cars can navigate a 15" R very well. But with close coupling some problems arise during pushing, where the endsill corners touch. During tests this did not derail cars, but it is not prototypical and could wear off paint. Fortunately the springs relieve the stress.
The problem can be corrected by adding the missing dead blocks (man killer's). Although in 1882, the MCB set a standard of an 8" square face and 6" thickness, with inside spaced 7" from center line, earlier dimensions varied drastically.
To assure function in model, an Evergreen .08" x .10" = 6.97 x 8.71" stip, cut to endsill height, is used. The striker, which should be removed, is shown in white, while the added deadblock is shown in yellow. The verical dashed line is at the link center point.
Note: Adjust brightness and contrast for optimum viewing.
DEAD BLOCKS ON 15" RADIUS
The ensill corners would just touch. Deadblocks extend about .005" past center and overlap by .0085", which should prevent hang-up. Corners may touch, without careful track work.
Note: Adjust brightness and contrast for optimum viewing.
DEAD BLOCKS ON 18" RADIUS
The ensill corner clears by .016" or .032" fo two cars. The blocks extend about .001" and overlap by .0085", which should prevent hang-up.
Coupling actions are not possible on common curves and are limited to tangents or very large radii. The spring action will duplicate the prototype movements that must have been present with hook and chain.
For knuckle couplers with 8 1/8" heads, the spacing will be wider at 27 1/2" or PF-ES =13 3/4" = .1579".
Note: Adjust brightness and contrast for optimum viewing.
NO PULL WITH 27.5" SPACING
The endsill to mounting center (ES-MC) = .188".
Note: Adjust brightness and contrast for optimum viewing.
KNUCKLE ON 15" RADIUS
The corner clearance is about .055" or .110" between 2 cars. Since the slack in pushing is .017" or .034" for 2 couplers, there should be no problem.
Note: Adjust brightness and contrast for optimum viewing.
KNUCKLE ON 18" RADIUS
EC clearance = .072" or .144 for 2 cars.
For mixing cars with different era spacing see MIX .
BACK TO COUPLER EXAMPLE INDEX
BACK TO KADEE 711
BACK TO 19TH CENTURY
