An interesting topic re the brass centreing spring for Kadee couplers http://cs.trains.com/mrr/f/88/t/278227.aspx?page=1 especially this post Harrison, the box spring is designed to "only" to be installed "on top of the coupler". If you look closely at at the spring you will see a big difference in the spring arms. As mentioned, there's a strong and weak side to help with uncoupling and delayed action. Also, note the end of the shank on the #5 type of couplers have different angles that are not symmetrical and these match the different spring arm angles. This is why it's important to always have the spring on top. If the spring is installed on the bottom it may work OK but eventually there will be problems. Note that when the couplers are coupled and in operation this takes the centering spring out of the performance issue so the spring on the bottom has no affect. It's when the coupler has to be uncoupled and centered properley that problems will arise and the spring may wear out faster. Remember that this is all late 1950s technology which is still the most popular in our coupler line, presently even more than our whisker couplers. Sam Clarke R&D Kadee Quality Products
