Tapering Blind Tender Wheels on 3rd Rail Locomotive

John I would try shimming the wheel set first to stop them from shifting and then see what has to be done to cure the issue. Shimming them may reduce the amount you have to taper the wheels and it may to consider replaceing the wheels with thinner units also. Just my two cents.

John,

Id taper the blinds sets to be the same width as the wheels with flanges. By width I mean the surface that be in contact with the rail.

@RJT posted:

John I would try shimming the wheel set first to stop them from shifting and then see what has to be done to cure the issue. Shimming them may reduce the amount you have to taper the wheels and it may to consider replaceing the wheels with thinner units also. Just my two cents.

Pretty sure just shimming them isn't going to do the trick, there isn't enough play to solve the problem with those fat wheels.

Replacing them isn't in the cards as they are not standard wheelsets, and I have no idea where I'd find something that would fit the tender.  The axles are a non-standard size for sure.

@Bruk posted:

Id taper the blinds sets to be the same width as the wheels with flanges. By width I mean the surface that be in contact with the rail.

That's my initial thoughts, but I was also wondering if I shouldn't start the taper a little sooner as I want it to be a gradual taper to allow the wheel to slide onto the rail in curves if it's off to the outside.  I've seen this mentioned in the past, but I sure can't find it now.

My sense was maybe to start the taper about where the flange starts on the flanged wheel sets, which would make the taper cover about 40-45% of the wheel surface.  I'm thinking around 20 degrees of taper, but the reason I'm asking is I don't want to screw up the only set of wheels I have!

John,

I have seen the same problem with the blind wheels on my AF Big boy, I just thought to avoid the situation that would cause this. Now reading your having the same problem the thought came to me to replace the wheels causing the problem with plastic wheels. Maybe just a brain phart?

Ray

If you are  going to turn it, you could step it down 1/64-1/32. I guess you would have to consider horizontal travel and width of the rail.

@gunrunnerjohn posted:

Pretty sure just shimming them isn't going to do the trick, there isn't enough play to solve the problem with those fat wheels.

Replacing them isn't in the cards as they are not standard wheelsets, and I have no idea where I'd find something that would fit the tender.  The axles are a non-standard size for sure.

That's my initial thoughts, but I was also wondering if I shouldn't start the taper a little sooner as I want it to be a gradual taper to allow the wheel to slide onto the rail in curves if it's off to the outside.  I've seen this mentioned in the past, but I sure can't find it now.

My sense was maybe to start the taper about where the flange starts on the flanged wheel sets, which would make the taper cover about 40-45% of the wheel surface.  I'm thinking around 20 degrees of taper, but the reason I'm asking is I don't want to screw up the only set of wheels I have!

You & Bruk are right on the money,...I’ve been through this before in that exact same application,....20-25 degrees off the backside to the same width as the flanged wheel sets did the trick,....just enough taper to clear the switch, but not so much to cause a slide off,....when you factor the contact patch of the flanged wheels, and the flange itself, you’ll see you’re not putting a whole lot of taper in terms of overall width .....you just need to clean up the fat wheels so they’ll clear, but still sit on the rail in a curve,.....go too wide, and they’ll slide off the rail in a curve,......I snuck up on the one I did,..

Par

I had the same type of problem with a UP 4-8-4' s  tender with the 14 wheel arraingment  John.

I like Ray's plastic wheel advice .  I think they would have to be smaller in diameter though .

My issue came on backing up the tender through some O31 switches.   I tried everything to get the issue resolved . I even made a deep radius on the inside and the outside of the non flanged wheels.      Somewhat succesful , but still had an occasional issue.       I finally gave in and replaced the 14 wheel arraingment with 2 six wheel trucks ............  No problem since, but to the person who wants to keep everything prototypical its a big nada.

I'm glad you had the photo of the wheels because it reminded me of part of the problem.........that front four wheels that rotate against the wishes of the rigid ten wheel arraingment had a tendency to put sideways pressure on  the tender and make it jump the track or drag on part of the switches.       

    I even thought of switching the front two rigid flanged  wheels with the second set of rigid non flanged wheels but never tried it.

Good luck

Can't you just shorten the Ross rail a little bit?

May I suggest basing your tapering on the taper found on some production locos with similar tenders? I checked my Lionel Challenger, but they are all flanged - however, I do believe that my MTH Niagara's PT tender (it's not handy right now) has some tapered wheels on some of the center axles.

Some blind drivers on diesels and steamers are tapered in the inside edge, of course - maybe emulate them so far as taper angle and depth of taper are concerned?

John, Don’s approach of shortening the rail with a slight twist. Shorten the rail a bit. Then insert a track pin and bend it down towards the ties slightly. Trim it back enough so the flanged wheels clear it. The wheels will ride over it. The pickup rollers will see it as a slight ramp and should still be able to create enough contact.

John, I second Don's suggestion. The fact the problem is associated with only some switches suggests the problem is variation in switches. I have had similar problems with both Gargraves & Ross switches which have been easily corrected by tapering, beveling or crimping rails and or inserting bent pins.

Shortening the rail is a non-starter.  First off, this is a customer's locomotive, so fixing it on my layout won't do him any good.  FWIW, I'm planning on tweaking all of the rails on this layout in any case as I have a couple of problem engines that hit the on the side.  However, as wide as these wheels are, I don't think just shortening the rails will do it unless I really went crazy.  However, since it doesn't really have to run on my layout, I'd have to fly out there and shorten all of his rails to actually fix the issue.

I have no idea where I'd find compatible plastic wheels, especially the color of these.  Also, I'm not really willing to go on a snipe hunt in hopes of finding something that would work and look right.

Given the nature of these wheels as well as the size, I think my only option is to modify this set of wheels.   In my mind, the tapering is really the best choice, but I only get one shot at it.  If I screw it up, I have a bigger issue in that I have to find the proper wheels to fix my screwup.  So, my mission is not to screw up!

@D500 posted:

May I suggest basing your tapering on the taper found on some production locos with similar tenders? I checked my Lionel Challenger, but they are all flanged - however, I do believe that my MTH Niagara's PT tender (it's not handy right now) has some tapered wheels on some of the center axles.

Some blind drivers on diesels and steamers are tapered in the inside edge, of course - maybe emulate them so far as taper angle and depth of taper are concerned?

My MTH Niagara was handy but it's tender has all flanged wheels just with a significant amount of lateral play in them.

@gunrunnerjohn posted:

Shortening the rail is a non-starter.  First off, this is a customer's locomotive, so fixing it on my layout won't do him any good.  FWIW, I'm planning on tweaking all of the rails on this layout in any case as I have a couple of problem engines that hit the on the side.  However, as wide as these wheels are, I don't think just shortening the rails will do it unless I really went crazy.  However, since it doesn't really have to run on my layout, I'd have to fly out there and shorten all of his rails to actually fix the issue.

I have no idea where I'd find compatible plastic wheels, especially the color of these.  Also, I'm not really willing to go on a snipe hunt in hopes of finding something that would work and look right.

Given the nature of these wheels as well as the size, I think my only option is to modify this set of wheels.   In my mind, the tapering is really the best choice, but I only get one shot at it.  If I screw it up, I have a bigger issue in that I have to find the proper wheels to fix my screwup.  So, my mission is not to screw up!

The lathe down in the basement of Hennings is calling your name,....pop the wheels off the axles, true them up in the chuck, and skin em on down,....you’ve got nothing to fear but fear itself,....😉

Pat

Pat, that's really a non-starter!  Wrecking the wheels with me at the controls would be plain stupid, I'm not going to do that!

@gunrunnerjohn posted:

Pat, that's really a non-starter!  Wrecking the wheels with me at the controls would be plain stupid, I'm not going to do that!

Plan B, ...place wheel sets in a small box attention to yours truly,....

Pat

After some measurements with O72 curves and the limits of the wheel slop, I've decided to remove 1.25mm from the inside of the wheels an put a very slight chamfer on the inner edge of the wheel.  That still allows margin to prevent the wheels from falling off the rail in a turn in either direction and looks like it allows sufficient clearance for the switch rail.

I'm still going to fix my switches to eliminate this issue, but I have to fix this locomotive anyway.

Have you asked Scott if they have seen this problem and devised a fix for that and future locomotives?

Jan

Not yet, I'm actually going to see what he has to say about the switches before I start hacking off rails.