Switch 'Picking'

[weinschenksk]

I am finishing laying roadbed and track on my layout....in testing it as I go, I have found that my locomotives are 'picking' a switch....i.e. front truck goes one way and the back track goes another.....I have tried several locomotives and each does the same.....I checked the wheel gauge and everything seems to be fine there....I am using Atlas #6's in N scale....any advice or guidnce will be appreciated.....thanks...

Sam

[Beach Bill]

Sam,

You may need to "dress" the switchpoints with a small file.  This will be delicate in N, but is something I have frequently had to do in HO, even with brand-name turnouts.  Look closely at the swithpoints where the problem is happening.  Does the point extend up a little higher, or is there a small gap between the point and the "main" rail?  If so, work lightly with a small file to shave down the point by working on the INside of the track.  Sometimes I have used a needlenose file to angle the top of the switchpoint a little more toward that outside rail - to reduce gap and also to improve electrical contact.

If the swithpoints look good, I would double-check the guard rails for clearance, as sometimes a tight spot there can cause a flange to ride up and over, which sometimes looks like a problem elsewhere.

Good luck.   My project for today is replacing a quality brand turnout in HO that, although brand new, is not functioning properly and my "tweaking" can't seem to solve it.  I want to make sure the track is proper before ballasting that area, so I think it's worth the cost to try a fresh one.

Bill

[selector]

What is the direction of travel, and at what point does your following truck appear to want to diverge from the path entered by the rest of the engine?  Is this happening near the frog, or at the points, departing diverging or on the through route?  We need a bit more information before we can help you to isolate the problem.

[Packers#1]

Same exact problem here: Atlas Custom-line (no switch motor) #6, no throws/anything, truck goes one way, rear goes the other. I was hoping that switch throws or motors would solve it. Thanks for the thread.

[weinschenksk]

 

thanks for the input.....here's some additional information....

With the switch et to the diverging route....to front truck of the loco will take the proper diverging route but the rear truck will follow the mainline....

I do appreciate any comments and/or suggestions since I am still just getting back into the trains....

 

Sam 

 

 

[larak]

Sam,

You may need to "dress" the switchpoints with a small file. 

...

Bill

NO NO NO NO NO NO NO NO NO NO

Before you take out a file and work on the frog......your FIRST step is to purchase an NMRA gauge.  Make sure ALL your wheels are in gauge and check the gauge of the switch.  Filing down a frog will do you NO good if your wheels are out of wack.

If your wheels are in gauge, and your switches are in gauge, then you will have great performance.

David B

David, looks like he was talking about filing the points not the frog.  That being said you are 100% correct about that NMRA gauge. 

Sam - Check the points (as noted above) both visually and with a fingernail. Then use the gauge on points, guard rails and wheels. ALL must be proper. Width, depth, etc. After that just move the engine very slowly and try to see exactly where the problem is occuring. This happens to all of us at some point. You can and will find a solution. Just remember to check the basics first and don't try irreversible solutions until you have no other options.

Karl 

[selector]

There is obviously something different between the two trucks.  If the first tracks true, then the points must be doing their job, and that truck's axles are in gauge.

For the trailing truck to not want to follow the defined path, it means the flanges are riding too high on the side where the point is thrown against the stock rail.  So, starting with a good visual inspection, is it possible that the lead axle is popped out of its journal slightly?  If it rides on the rim of the journal hole, that 1 mm difference takes the flange right out of contention  since an RP-25 flange will be about that deep.  If all axles are properly mounted, then the truck is bent and causing the leading wheel on that side to ride high...at least, that is a possibility.

Another is that the truck may have some flashing that prevents it from swiveling and tracking properly.  When the truck is sitting on the rails, it is pressed harder against the underside of the cab than when it dangles as you manipulate it to rail it.  So, while it may feel normal during railing, it isn't normal when it is doing its tracking.  Remove the truck and feel with a finger tip around the mount, both on the cab underside and on the truck.  Also, look for piping or something else that may not have been installed properly, or that has been bent in packaging, and that prevents the swing of the truck.

That's about all I can come up with.

[Beach Bill]

Sam describes the problem as happening with a number of different locomotives at this same point.  He also says that it is a problem with this one turnout.  That suggests that it is indeed the turnout rather than that the gauge is off on each trailing truck. 

One other possible variable is if this turnout is at the base of a grade, where the slack of the following train may be pushing against the back of the locomotive's tender and affecting the tracking ability.  Usually, in testing to identify a problem one doesn't use a full train, so that is unlikely, but is possible.

Suggestions on checking everything with a NMRA gauge are correct, and a gauge should be at the top of your "to purchase" list if you don't have one.  They last forever.  One can also make a flatcar out of clear plexiglass that allows you to look directly down at the turnout as the test car goes over it - such "clear" flatcars for track testing are also available commercially.

Sam - when you resolve the problem, please share with us what you found.  Troublesome turnouts can be frustrating, and there have been times that I have had to come back and look at them fresh the next day to help maintain it as a fun hobby.

Bill

[delray1967]

Could be the turnout is a bit too low or the frackwork leading to it is a bit high.  Sometimes glue can raise trackwork just enough to make trouble for those locos and rolling stock that are just a .001" too tight.  Place a good starightedge across the railhead and look for any high or low spots.  Check 6" before and after the turnout as well as the turnout itself.  Maybe there's some foreign oblect in the flangeway?  Maybe the car that is coupled to the loco is causing the extra sideway motion?  Maybe you're running too fast through the turnout, do the locos derail consistently at all speeds?  Watch it closely at the slowest speed possible and see exactly where the flanges start to ride up.  Just like a watched pot never boils, a watched wheelset never derails...keep watching those trains!

[jfugate]

One very subtle problem that can exist with trucks is for both wheelsets to be in gauge, but for one wheelset to be at a different location on the axle (measured from the end of the axle) than the other wheelset.

What this creates is a truck that runs down the track at a slight angle and it will pick turnouts like nobody's business.

One easy way to find out if this is the problem is swap trucks end for end. If this is the issue, then the other truck will start picking the points!

If this is so, then the fix is to replace the wheelsets in the bad truck. 

[weinschenksk]

As usual, when you post to the forums you always get good responses......tanks for all of the input.....lots of things to check.....Ihave printed out all of the suggestions and will begin attempting to find the problem....if and when I find the solution, I'll be sure to post my findings....again, thanks for all the help you have been.....I read the forums almost everyday and now have a wealth of information as I continue to build and scenic my layout...

 

Sam