4-6-0 derailing?

[Selector]

When you remove the front truck, how does the mounting bushing surface under the frame feel to the lightly polishing finger tip? Is there a high spot or an obvious burr of some sort...maybe some flashing? How about on the mating surface on the bolster of the truck? I wonder if a spring is missing that might allow some freeplay so that the truck wobbles just a bit more and can rise and fall a bit as well.

I assume wheel gauge has been checked. The loco has no parts added by another person, or modified parts added by a previous owner that has changed the loco from its original looks and configuration?

It does sound to me like the truck is prevented from swinging sideways when it needs to, but also it is being forced into yaw by something which understandably would horse one of the wheels up away from the rails...or both on that side if a four-wheeled truck.

 

[skypup]

Might sell.

The truck had the screw,spring and bushing installed. Guess I can take it apart and check the fit and finish of the truck/bushing. It's a nice loco. I may be switching to ON30 so I may just put it up on ebay and mention using a 22" radius if I can't make it work. Where is a good place to sell locos? I'm use to r/c aircraft sales but not trains. Thanks.

 

[Cjcrescent]

The pilot (cowcatcher) should be removable by means of a small screw that goes through a hole in the front end of the frame downward into the pilot casting. You'll probably have to remove the boiler to get at it. As shown in the diagram, the pivot screw for the lead truck also holds the boiler and cylinder block to the frame.

On this model the pilot is molded as part of the frame. The screw in the diagram merely holds the coupler in place.

If you are leary of trying to bend the pilot extension upward, you have two choices. Either file some material off the frame or the pilot extension so as to raise the pilot up. One other thing you might consider is to replace the pilot altogether with a different one. Cal-Scale makes several "wooden"-style pilots, though you'd have to see which one would go with your locomotive.

Green board all the way!

I think that you nailed it here! File the front down or replace it with a brass casting.

I checked everything again. On a glass table there is clearance, of course on the rails that changes. Going around an 18" right hand curve the front two lead wheels on the truck move to the left leading to the derailment. The front left wheel lifts off of the track and the left wheel is outside of the rail leading to the derailment.

Sounds like there isn't enough downward pressure from the spring that is supposed to be under the truck. I would either place small lead weights on the truck to add some weight to it , or stretch the spring a little, if there is one there, to apply more downward force, and possibly stop the yaw that Selector is talking about.

 

[trailrider]

Check the slot in the truck that the mounting screw goes through. It is possilbe there is a burr in it. You may need to elongate the slot side-to-side to allow more swing. The other thing that needs to be checked is if the wheels are hitting the inside front corner of the cylinders. That can be fixed by simply filing off more material. You won't see it when the engine is running.

I just found a great supplier for Mantua parts: Yardbird Classic Trains (www.yardbirdtrains.com) They've got gearboxes and replacement motors that could make it easier to add sound decoders, etc. When I get time, I may go crazy!

Green board all the way!

 

[skypup]

I stretched the spring and added some tri flow oil to the truck. It was a longer run but still derailed.

 

[SABRR]

I stretched the spring and added some tri flow oil to the truck. It was a longer run but still derailed.

Stretching the spring will only make the situation worse and won't solve the tracking problem. Let's take a look at this:

A. Looking at the front bogey, is the slot where the bushing sits in worn any? Does the bushing show any abnormal wear?

B. Next thing to look at is if the drivers are uneven in their cavities. If one driver is sitting lower in its slot than the other that can present a problem. Remove the screws holding the retaining plate and remove it. This will expose the axle shafts. Look at the underside of the retaining plate. Any wear marks?

C. Remove the drivers. Check the brass bushings. If you are missing one, then they need to be replaced. If they are worn, they need to be replaced.

You can get these simple parts from Dan at Yardbird trains for next to nothing. A little tweaking of your steamer wouldn't hurt anyway.

 

[Cjcrescent]

Stretching the spring will only make the situation worse and won't solve the tracking problem. Let's take a look at this:

I'm owned several of these over the years, and if the spring provides little or no downward thrust, the front truck will derail.

A. Looking at the front bogey, is the slot where the bushing sits in worn any? Does the bushing show any abnormal wear?

I don't want to sound snotty but he's been asked to do this by several folks already. Apparently there is no problem there.

B. Next thing to look at is if the drivers are uneven in their cavities. If one driver is sitting lower in its slot than the other that can present a problem. Remove the screws holding the retaining plate and remove it. This will expose the axle shafts. Look at the underside of the retaining plate. Any wear marks?

C. Remove the drivers. Check the brass bushings. If you are missing one, then they need to be replaced. If they are worn, they need to be replaced.

You can get these simple parts from Dan at Yardbird trains for next to nothing. A little tweaking of your steamer wouldn't hurt anyway.

Ah! Didn't think of the axle bushings! However, I would also put the loco back on the piece of glass, and see if any of the drivers are off the glass. This could indicate either worn axle bushings or even a slightly bent frame.

I would also put the truck on the glass by itself and see if it is warped. If all 4 wheels don't touch the glass, a warp in the truck frame is possible.

But if all this still results in no problem being seen and the loco keeps derailing, I believe that its still the track and not the loco causing the derailments.

Its always hard to diagnose the problem when we don't have the loco & layout directly in front of us. So please be patient with us.

 

[skypup]

Thanks for all of the replies. I sold it on ebay with a caution to run on 22" radius and replaced it with a spectrum MA&PA 4-4-0 with DCC and sound and NCE cab. I should have them in a few days.