I have just been running seven new Rapido coaches and going forward they run great. However in reverse they will sometimes derail and it appears the diaphrams are binding pushing the cars off the track. I was wondering if the diaphrams will losen up after awhile and this will eventually stop. My minimum radius is 31" Thanks for any thoughts on the matter.
Brent
Brent, I had the same issue on larger radius [36"] so i just replaced the factory couplers with a longer shank kadee coupler; I require all my rolling stock to use kadee couplers so I planned on replacing the factory plastic couplers, however the initial test runs revealed that longer couplers would be necessary to prevent the diaphrams from causing derailments. Now the cars do not derail. For passenger consists that won’t be broken up and switched, it will suffice to use a medium shank coupled to a long shank. I use Kadee no 148 [medium length] coupled to no 146 [long length] with reliable results. Note that these are the ‘whisker’ couplers and reliability has so far proven good. The whiskers are also a bit easier to install as they do not require installation of the centering spring.
Look for flash on the diaphram end plates. Also, make sure the trip pins are at the proper height.
David B
The problem appears to an ‘engineering’ issue as it only occurs in reverse coming out of a curve; as the diaphrams come back together it causes the car to be lifted. It is not an issue with track, wheels or couplers as it happens with different rapido cars at different places. This a characteristic of the car that needs to be considered when outfitting them for service on a layout; replace the couplers and the problem no longer exists. Otherwise these are very attractive cars that I enjoy running.
Thanks David there are definitely burrs and rough spots on the two diaphragms that are causing the problems. How would you suggest smoothing these out? I have most of the tools but am inexperienced in dealing with delicate things like these diaphragms. Also the trip pins all needed adjusting and my vendor told me about the problem when I picked them up and also showed me how to bend them up.That problem was dealt with as each coach went on the rails for the first time.
Fisker thanks for the coupler size recomendations. I was thinking that I may have to do this if all else fails. I really like the close coupled look so will work long and hard to make the originals work.
Brent
The diaphragms are not all that delicate. Just trim them with an exacto knife. Check your work with your finger until the burrs are gone.
Every Rapido car I have owned has had this issue, but it is a quick, easy fix.
David B
use some light sand paper [#300-500], an emery board, or a small modeling file and go easy; less in this case is more. As to the couplers, using a long-medium combination provides an additional 3/32 of space. The resulting space is not discernable to the eye from normal viewing distances, but makes for better operational reliability and also makes it easier to uncouple cars. As for the factory plastic couplers there are whole other thread on plastic knuckles vs kadee/metal. I believe the general concensus is over time the plastic ones will fail at the most inopportune time. Murphys law at work. Food for thought.