Does anyone have a fix for a BLI J1 and wobbles as it goes around a curve. I wonder if it is that the drivers are not true. It doesn’t wobble on the straights though.
Help anyone?
When I see wobbling from a large engine with fixed drivers under the boiler along curves, it tells me that the curves are either too tight or they are in and out of tolerance for the line that the flanges want to conform to based on the engine’s design. If…if…the drivers are truly in gauge, and they all move in the range up and down and sideways that the manufacturer intended for use on typical model railroad trackage, then you should assume one of three things:
a. your rails are out of gauge along that curve or at the entrance/exit. Check in about 10 places;
b. the curve is actually too tight in radius at some point, or all along the curve. Meaure and ensure that your curve is a true 23". It will do small-“O” okay on 22" curves, despite what BLI claims, but you will have to almost walk it through them. 23" will be better, and 24", their claimed minimum, is just fine. I only use a 24" min in my yards and industrial tracks, so no probs with my J1; and
c. your roadbed is not level along your curves and the rails therefore dip here and there. This usually results in derailments with the larger engines, but if it is not that bad, they may simply wobble.
Edit- there is one other remote possibility, and that is that one or more of the driver pairs is slightly out of quarter. However, this would result in a lurching, wobbling loco at all times, not just on curves.
One last even more remote possiblity is that a retaining nut may have backed out of one of the rods, or one of the rods may actually be bent so that when the loco goes around a curve, the driver(s) work outboard and the nut or rod swipes or impacts momentarily with others or part of the frame.
Selector gives some good advise. I have to second the quartered drivers. If the engine had any drivers that were out of “quarter” then it would run for a inch then completely jam. If it were 1 driver out of “quarter” then it would do it every revolution, not just in curves. And I also second the curves being to small of a radius. Those big monsters need a big radius to run.
You can place your J1 upside down in an V padded shapped cradel type of holder and use electrical wire clips to the tender so the engine can be run upside down. This will allow you to observe the running gear and verify the drivers are runnng true. You can also place slight presure on the sides of the drivers to simulate a curve and observe that is going on. The J1 has a blind driver for the third set of driving wheels and this set might be riding up on the curve and catching in some sort of stange way, especially is the curve is super elevated.
The J1 is very long in the driver wheelbase and the center blind driver can do funny things on curves.
Good luck with finding out what is causing this.