I've added Kaddee couplings to classes 156, 158 and 170. The couplings I used where no.5s. For fittment on a 158 you need to remove the orginal plastic couplings and the raised area round the locating pin for it, this is much easier of you remove the body. If its a car with a metal I just put plastic card round it to give a flat surface to locate the coupling on. You will need a height gauge to check the coupling levels. I then jus secured the couplings with super glue, as they shouldn't be under to much pressure. just be mindful that when reattaching the body that the coupling has to go through the orginal coupling hole.
Points to note:
- unless you have very large corners you will not get close coupling on the straight. The couplings don't extend on corners, so the back of the coupler knucle should be level with the front of the gangway. On 170s its more a case of guessing. Also with 170s the snowplough under the main body needs to be adapted to allow the coupler to fit.
- Height matters alot to the couplers, so always test your couplings before use! Some of the uncoupler pins may catch on code 100 point work, a problem which is easily solved by snipping off the bottom of the pin. Just be careful as you need most of the pin there to automatically uncouple the units.
- They will NOT go round radius one curves. All curves ideally need checking before use, especially raduis two curves. My units can handle radius 2 curves, but have a tendency to "twist" on the tightest spots. If your in doubt fit a couple of wagons with Kaddees using a temporary fitment (blu-tak maybe?) and test the corners. The same applies to point work they won't go through Hornby points but go fine through Peco points even complex double slip and three way points.
Hope this helps, Michael