On the SJR&P many of our C-19 locomotives have battery packs in the tender for the purpose of DCC backup power. One side effect of this is that the tenders are heavier than stock tenders.
Yesterday the tender of one of our C-19 locomotives kept derailing, a condition we have not seen before.
On close inspection I found that the rear truck side frames were hitting the tender frame interfering with the trucks ability to rotate through curves. While the truck side frames are intended to have some play, the play on this truck was excessive.
On disassembly I found that the single spring that is inside each side frame had collapsed. I replaced these springs with springs Bachmann uses on its 1:20 freight trucks. After replacement the tender truck now operates like new.
This particular C-19 was one of the first to receive a battery pack. Inspection of other C-19s with battery packs showed several that were beginning to have excessive sideframe play but not the extent the problem one had. Each will have its springs replaced as well as a preventive measure.
Below is a photo of the collapsed spring next to a new one.
Stan
