Got a BLI C&NW 2-8-2. It runs around both mainlines in both directions without a problem…except for one turnout where it falls off the track onto its side when crossing on the straight through route. It passes through every other turnout without a problem. No other steamer has a problem running through this turnout.
What is happening is that the pilot wheels cannot stay on the point rails.
The turnout is an Atlas Code 83 #6 Custom Line.
Is it the loco or the turnout or both?
Rich
I had a problem with my BLI Mountain (a few years old) wanting to derail by climbing the rail when backing through a particular turnout. I had the turnout twisted somewhat, but the Mountain was still good at being the only one to try to derail after tinkering. My LHS guy took some play from the drivers with some fiber shim washers, a partial help. He tried changing the driver springs but that didn’t help. He then tnkered with the trailing truck, which helped more.
Rich,
Gauge is OK?
Not familiar with that loco. Is there any springing associated with the pilot truck?
A couple of ideas, Rich. Is the loco so long that its wheelbase is partially on curved rails still…rearward? I can’t see this happening on anything more than a real #4 that is small enough, but a #5 turnout and on up would have the entire driver axle set on the turnout at or beyond the points looking toward the frog. So, the pilot wheels are picking a guard, or maybe picking the frog point…?..not sure. You’ll have to perform trials with really strong light and the loco doing no more than 15 scale mph. Try three different speeds, 15, 10, and crawl…speed step 1. You WILL see that single axle on the pilot truck lifting at some point.
Secondly, and separately from possibly a tight flange gauge between the guards and the closure rails, it might be as simple as a set of flanges just half a mm too tight. Remove the axle, twist gently and just get one of the wheels to budge. Gauge them accurately first, noting how they fit in the grooves, then gauge them again to see the miniscule change you want.
Or, the track guage at the hinge, or near the frog, is narrow/wide…you have checked it? The point rails are firm and don’t wobble?
Lastly, and it’s a bit of a longer shot, the two wheels are in gauge, but both slid over to one end of the axle by enough that the one flange does pick the guard or the frog.
I doubt you’d have so basic an error as to have the entire turnout on unstable roadbed such that is sags or rolls a bit under the weight of the loco. I have already earned my badge for that screwup, believe me, but it is now getting quite dusty. Earned that with my then-new Lionel HO Challenger running over what were the only ‘long’ turnouts available on EZ-Track in 2005.
-Crandell
The pilot wheels are in gauge. The trailing truck has a coiled spring, and the pilot truck has a leaf spring.
Rich
Crandell, you have superb detective skills.
I wound up lightly pushing the loco by hand onto the turnout. The pilot wheels make into onto the point rails, but the first set of driver wheels lifted as they reached the point rails. Didn’t see the problem at first, but then I realized what was happening. The point rails are held in place by plastic tabs. Turns out the driver wheels were running up on one of the tabs which was shoved up on the point rail assembly. Amazing, and more amazing is the fact that no other loco was affected. I have some extra throwbar assemblies, so I will replace it in the faulty throwbar assembly in the morning.
Thanks all for your replies.
Rich
if you could replace this turnout with any other one on the layout that you don’t have problems with, do you think you would still have a problem?
if the problem can be fixed by doing something to the loco, why only this turnout? Do both need some adjustment?
If I had a spare turnout to replace the one causing the problem, I am quite sure that the problem would go away.
But you raise a good question. Even with that raised tab that has climbed onto the point rail, no other loco derails on that turnout. So, the raised tab alone is not a fatal flaw. There is something wrong with the loco as well, and I suspect that it is that first set of driver wheels. They don’t seem to be sufficiently springy to aborb the minor shock of the raised tab.
I have had some problems in the past with the driver wheels locking up on this loco on occasion. I am going to have to look closer at this problem as well.
Rich
Bet the point rail has come adrift fromt he throwbar plastic. I’ve seen this on Atlas turnouts, mainly ones that were subject to too much force ont he throwbar. The plastic is C shaled, open side facing the stock rail on that side, the point rail slips in and has a little hole that is supposed to catch in a tab on the palstic. This can come loose and so when the points are moved, it pushes the larger hump of palstic tight against the point rail. Ordinarily there is way more than a flange width clearance there, no way should a wheel ride up on it. But if broken in this manner, the raised part is right against the point and this will happen. Usually it’s not permanent - just hold the affected point rail and pull the throwbar away until it snaps back in. But if using solenoid switch machines, or a Tortoise with the fulcrum set to give too much force, it will happen again.
–Randy
Randy, that is a perfect explanation for what is happening. For whatever the reason, the tab won’t stay down. So, I will swap out the the throwbar assembly with a spare this morning.
I have had the point rail slip out from under the tab before, but I have never seen the tab spring up against the point rail like it is doing here.
I will report back after I replace the throwbar.
Rich
Rich,
Having a similar problem with an IHC on an Atlas #4. Have received a lot of advice, but the loose throwbar is new. Very frustrating when it is just one loco on one turnout. Goes off when coming in off a straight section of track into the single end of the turnout and it tries to go the dirverging route when set for straight. I did replace the turnout, it improved, so that now is just the one loco, but still have a problem. Now will check to see that the turnout is sitting level, but will check the throwbar too.
Good luck.
Richard
Richard, let us know what you find out. As I say, in my case, it seems to be both the turnout and the loco.
Rich
Rich
Closely look at both rails joining the turnout and track entering/leaving the turnout. If it’s a tad as as-cue, that might be the problem.
Joe C
Here is an update on my issue.
Somewhat excitedly, I swapped out the throwbar. But, much to my chagrin, that made no difference.
So I went back to running the loco through the layout at the slowest speed. What I noticed was that as the pilot wheels came sideways off the rails, the driver wheels remained on the rails. Exasperated, I took the pilot truck off the loco. Fortunately, the engine is sufficiently balanced that it could run without the pilot truck attached. Lo and behold, it flew through the turnout at the highest speeds.
Not sure what that suggests. Are the pilot wheels out of guage? Is the pilot truck simply misbehaving? I had added weight to the pilot truck last night, but that made no difference.
Any further thoughts?
Rich
Did you try filing the points where they touch the stock rail ? If you can run your finger along the main rail and catch your finger on the tip of the point rail, your wheels are probably catching it too. Take a file and slightly bevel the tip of the point rail where it touches the main rail until it feels smooth as you run your finger along it. I’m betting your pilot wheels are “picking the points” and not following the rail - pilot trucks are notorious for that.
Mark.
I will give that a try, Mark.
Rich
At this point I would inspect the bearing surfaces of the truck, both the mounting area on the loco’s frame and on it’s pivot bearing. Look for flashing, or contact somewhere with something ‘sticking out’. It should be a heavy enough truck to ride nicely by itself, barring a rolling or yawing frame caused by a non-flush turnout…all rails surfaces at mean grade.
You have gauged the rails from the points, throwbar set both ways, all the way through the turnout, both routes?
If the bearing surfaces and protrusions present no problem, then try adding either a coil spring or some weight.
-Crandell
I have a feeling, MARK’S reply is the problem. You didn’t mention if you tried that. The pilot wheel set may have a tighter wheel to rail ratio, then the others and it will pick the blunt point.
Frank
I did go down and try that, but the point rails are nice and smooth and tuck in against the stock rail.
The problem definitely seems to be the wheelset on the pilot truck. But, why just this one turnout? Interestingly, I took the wheelset off the pilot truck and looked it over, then put it back on the truck, It ran through fine. I don’t expect that to last, but I will test it again this morning.
Rich
Rich, I had a Mantua that would throw the front pilot off one turnout; no other locos had problems. After much frustration, I finally discovered that the wheelset would periodically quit turning, and that is when it would derail. After cleaning it well and ensuring the wheelset was running true and not able to rock or get cocked in the pilot, it now has no problems. You may have stumbled across something very similar and by pulling it apart you may have dislodged or otherwise free’d something up in there. Hope it stays running well for you!
Duane