Large Scale Central

Pilot lifts off the track going through switch

Problem Solving
#1

I swear I can’t figure out why this happens. The pilot on my Christmas train is jumping the track again this year. I’ve had years where this never happens and some like now where it does. I can’t figure out why this is happening and sure could use some help. At least every other time pushing out of this switch the pilot derails. The switch is set so that the train rolls into the loop automatically and then coming out of the loop pushes the switch rail to the other side allowing it to exit.

Here are 2 videos. One in normal speed and the other slow motion.

Normal speed:

slow motion:

#2

Are the rails of the switch in gauge?

#3

Not enough weight to push the points over? Will it go through OK if you throw the switch manually so it’s not pushing the points?

#4

Sorry Tim, I shoulda known you already weighted the pilot!

#5

Rick Marty said:

Are the rails of the switch in gauge?

Don’t know. How do I tell?

#6

Jon Radder said:

Not enough weight to push the points over? Will it go through OK if you throw the switch manually so it’s not pushing the points?

Last year it worked just fine. The year before I had an issue but it fixed itself. This year, about every other time it exhibits this behavior. I’ve tested this with 3 other locos and the same thing is happening. I will check to see if it can go through the switch when switched manually.

#7

John Passaro said:

Tim, those floppy front trucks are a pain in the you know what. I know guys who just plain flat out remove them and leave it at that. Fortunately they are usually dangling by one screw. Me, I add weight. Here’s what I do, using lead weights.

Notes: I would have used the steel shim instead of a piece of wood as a platform, but I couldn’t cut the shim without destroying the blade on my chop saw. Second, you see six weights, but the front three interfered with the normal swinging of the pilot arm, so I flattened them with a hammer and used two instead of three. The “glue” for all this is Powergrab. Finally, I painted everything black so my modification would blend in once installed.

Hope this helps. (If it doesn’t work, you can always toss 'em; nobody will notice.)

The pilot already has added weight which I glued on numerous years ago.

#8

I would use the auto mag wheel stick-on weights sold a auto parts stores. can be cut with wire cutters to any length, but in most cases they are designed to be cut, or broken to a desired length. Must easier installed and come with double sticky tape, plus can be used on the under side of rolling stock for additional weight when needed.

trainman

#9

timmyd DeHan said:

…

The pilot already has added weight which I glued on numerous years ago.

I don’t know what else it could be…in the video all the other, heavier, fixed wheels go through fine. I’ll be interested to see if you or somebody comes up with an explanation.

EDIT: I do notice that the pilot wheel rides up over whatever part of the switch that is, instead of the wheels “forcing” their way through. Maybe tighten up the pilot some, if there is a way of doing that, so that the pilot set isn’t as “floppy.” I’ll try it on one of my steam locomotives and see what happens.

#10

When I gently push the loco through the switch it sometimes is not pushing the points over and is riding up on the rail. This is what is causing the right wheel to lift up and swing the pilot off the rails. I don’t understand why it happens sometimes and not other. I tried cleaning the switch and that didn’t help. So, I replaced the switch with a brand new one I have and it appears to be working.

#11

It seems tolerances are at play. The pony axle back to back wheel spacing may be a bit too wide (nominal back to back spacing is 1.575 inch) whilst the spacing of the switch point rail to stock rail may be somewhat tight.

-Ted

#12

Ted said it, also double check the pilot wheels spacing, it may be slightly out of gauge.

#13

Ted Doskaris said:

It seems tolerances are at play. The pony axle back to back wheel spacing may be a bit too wide (nominal back to back spacing is 1.575 inch) whilst the spacing of the switch point rail to stock rail may be somewhat tight.

-Ted

I will check that.

#14

I took the pilot off the loco and first eyeballed the wheel spacing. I can see that the left wheel is not balanced. I took 4 measurements in 4 different places. Here is what I got.

1.5875

1.577

1.586

1.573

How do I got about correcting this?

#15

Timmyd,

It’s common to have some amount of wheel run out. If wheel back to back spacing is too wide, the wheels can ride up over the rails. That said, your wheel back to back measurements do fall into the acceptable range of NMRA Standards 4.2, more particularly 4.3.

NMRA Standard, S4.2 Scale Wheels

Scroll down to page 3 in this standard for Scale LS

With this standard it can be seen tolerance for back to back wheel spacing can be from 1.570 to 1.594 inches.

NMRA Standard, S4.3 Large Scale Wheels Standards Wheels with Deep Flanges
(This looser standard seems to “grandfather” early large scale manufactures like LGB & Aristo-Craft having typically narrow back to back wheel spaced products)

Scroll down to page 2 in this standard for Scale LSdf

With this standard it can be seen tolerance for back to back wheel spacing can be from 1.560 to 1.594 inches.

-Ted

#16

Tim said:

pushes the switch rail to the other side allowing it to exit.

Ted suggests:

It seems tolerances are at play. The pony axle back to back wheel spacing may be a bit too wide (nominal back to back spacing is 1.575 inch) whilst the spacing of the switch point rail to stock rail may be somewhat tight.

I can’t see how the back-to-back spacing, or the point rail to stock rail gap, affects whether the pony wheels push the switch out of the way, or not in this case.

Tim, if you google “site:largescalecentral.com spring switch” you will find a few threads where folk tried to make a spring switch - which is what you have here. In my experience, sometimes they work and sometimes they don’t. Sometimes a loco works, and sometime it doesn’t. (Sound familiar?)

Not only is the weight of the pony truck important, but also the spring of the switch. There may be dirt in it. The ‘spring’ (whatever it is) is now a year older and may have been stored so it isn’t working the same as it did last year. In your case, the spring has to be just enough to return the points after the train passes through - no more, no less. Once you have established that springiness, then you can add weights to the truck until it pushes the points out of the way.

And you can expect to have to research this every year (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)

#17

Add weight is great, also a stronger spring will help also. This worked great for the USA Hudson.

#18

Dan, do you have a spring that you or the other techs recommend for this application due to experience? Maybe one of you have worked on this model before. Or, do you sell a variety of the springs that fit this loco’s pilot so he can have a kit, so to speak, of springs with different force strengths (not sure of the correct word here) to try and get the correct one?

#19

Dan, do you have a spring that you or the other techs recommend for this application due to experience? Maybe one of you have worked on this model before. Or, do you sell a variety of the springs that fit this loco’s pilot

The springs are for the switch track point blades. While it isn’t unusual to have a spring on the pilot truck to keep it down, I was referring to the problem of pushing the switch point blades to one side. If they are too stiff the pilot truck will lift over them - as Tim’s video shows.

#20

Ok… status update:

  1. I acquired 6 1/4 oz. square mag wheel weights and applied 5 of them to the pilot. it is definitely heavier!

  2. I replaced the switch mechanism to a new one.

  3. I applied graphite to the switch mechanism.

  4. I also put a very thin piece of wood strip under the right rail of the switch as the train enters as it appears it was dipping down.

  5. I’ve run the Trian around the double revers loop now for about 20 minutes with no derails.

so…I’m not sure what fixed it but it appears to be ok now. I will post a video of this years Christmas Train layout. However, in the meantime here is a video of last years Redmond Creek RR Christmas Train double reverse loop.

Thanks everyone for all of your suggestions and help. Happy Holidays!