MTH 4-6-2 Derailing on switches

I would first check that the switch points make solid contact with the stock rail, if the switch point have a minimal force contact with the stock rail these point can float and derail the engine, car or caboose. Also check that the guide rails are rigid and in the correct position.  

Thanks for the reply John,

From what I can tell the switches seem solid everything is rigid aside from the parts that are supposed to move, and the switch point sits flush against the rail without any play in both directions of travel. This derailment only happens with the rear truck of the steam loco rolling stock is able to pass through without incident as well as diesel power.

Jagger19 posted:

Thanks for the reply John,

 

From what I can tell the switches seem solid everything is rigid aside from the parts that are supposed to move, and the switch point sits flush against the rail without any play in both directions of travel. This derailment only happens with the rear truck of the steam loco

The "rear truck", i.e. trailing truck of the engine, or the "rear truck" of the tender?  Something may be restricting the travel of either.

rolling stick is able to pass through without incident as well as diesel power.

The tender is able to pass fine, its the trailing truck on the engine. I have it in the cradle at the moment and it is able to swing in either direction freely without any restriction. That was a friends first suggestion but I do not see any obstructions.

If nothing changed but the loco, it's the loco/tender. During this "board change" was any running gear removed, etc.?

Im not sure, I did not perform the repair my local hobby shop did, but the engine was running just fine until yesterday. The repair occurred in February so i don't suspect it was that unless something wasn't done right and the part was only working for so long?

A new development, I reversed the engine in the direction of the switch it normally travels (clockwise instead of the usual counterclockwise) and the rear trailing truck on the engine clears both switches on the loop with no problems. Noticing this I flipped the engine around in the opposite direction and ran her and again no issues other than a hop on a rail joiner because atlas doesn't T the frog portion of their switches so I removed that joiner and the hop is gone. However the rear truck still derails in the forward direction (counterclockwise) during operation.

Yes there is and it applies downward pressure to the track. Here is a link to the model

https://mthtrains.com/20-3460-1

Jagger19 posted:

The tender is able to pass fine, its the trailing truck on the engine. I have it in the cradle at the moment and it is able to swing in either direction freely without any restriction. That was a friends first suggestion but I do not see any obstructions.

In your other post on this you mention it derails going straight. Clearly not an issue of the trailing truck swiveling. As mentioned, how does the switch look? Does it do it with and without a train behind it?

Its a possibility but it still seems strong to me. I think Ive narrowed down the issue. On the atlas switches they use plastic tabs to attach to the arm that pivots. The rear truck somehow catches the inside tab (the side on the inside of the oval) and that's whats causing it to "hop". At least that's what I believe I am observing now running it in the regular direction again but it doesn't happen in the reverse direction.

When something like that happens to me, I put a little weight on the trailing truck. I have stick on weights of about 1/2 ounce that work well. A 1/2 oz nut might do the job.

BobbyD posted:

Jagger19 posted:

The tender is able to pass fine, its the trailing truck on the engine. I have it in the cradle at the moment and it is able to swing in either direction freely without any restriction. That was a friends first suggestion but I do not see any obstructions.

In your other post on this you mention it derails going straight. Clearly not an issue of the trailing truck swiveling. As mentioned, how does the switch look? Does it do it with and without a train behind it?

Yes it derails pulling a train behind it. I am currently working on building the layout before I put roadbed down and ballast the track.

gftiv posted:

When something like that happens to me, I put a little weight on the trailing truck. I have stick on weights of about 1/2 ounce that work well. A 1/2 oz nut might do the job.

Thats something I haven't considered yet, do you use double sided tape to adhere to the truck?

Try installing the plastic ramp on the center rail at the center of the switch.  NH Joe

New Haven Joe posted:

Try installing the plastic ramp on the center rail at the center of the switch.  NH Joe

I will give that a shot when I get a moment, do you think something is catching on that V in the switch? I'm just curious I know the instructions say that helps for certain cars that have activation points. 

New Haven Joe posted:

Try installing the plastic ramp on the center rail at the center of the switch.  NH Joe

Just tried it on both of the switches and still experiencing the rear truck hop.

I have however noticed something else with my flashlight, the trailing truck isn't resetting to center on the post it rotates on under the chassis. See the attached pictures here of the derailment. Its hard to tell but the trailing truck has no more room on the screw to swing as it is maxed out from the last turn it made and hasn't reset back to center. There is a grounding wiring one the trailing truck but it doesn't seem to impede movement of the truck at all.

So with this being deduced I think now i have a good understanding as to whats going on. From the way I see it the engine goes around the turn just fine but the trailing truck is pushed to the end of its slot in the chassis. When the engine comes to the switch the flange on the trailing truck catches the plastic tabs used to actually throw the switch causing it to "hop" which in turn derails the locomotive. The question is how do I fix the trailing truck so it properly resets itself once the locomotive comes out of a turn onto a straight away?

jagger19

Sorry to hear of you running issues with the MTH engine. I feel your pain.

My layout has been around over 40 years and has 27 Marx 1590 switches and is 027.  I still have the running problems with most new to the layout engines.  It always takes awhile to figure out what the cause is.  I have most issues with 8 drive wheel engines, diesels, and 4 wheel leading trucks.  Most recently was a Marx 333, 4-6-2 and the sliding power pick up.  This was only on one of my to 333s.  The one before this was a new Lionel 561, 0-8-0 switcher.

Charlie

Choo Choo Charlie posted:

jagger19

Sorry to hear of you running issues with the MTH engine. I feel your pain.

My layout has been around over 40 years and has 27 Marx 1590 switches and is 027.  I still have the running problems with most new to the layout engines.  It always takes awhile to figure out what the cause is.  I have most issues with 8 drive wheel engines, diesels, and 4 wheel leading trucks.  Most recently was a Marx 333, 4-6-2 and the sliding power pick up.  This was only on one of my to 333s.  The one before this was a new Lionel 561, 0-8-0 switcher.

Charlie

Good afternoon Charlie,

How have you gone about fixing the issues you have run into? In my particular situation I will be placing an order for 1oz tire weights that I plan on placing on the trailing truck to see if it corrects itself on the straight sections. I planned on using the weights on some of my freight cars to weight them to NMRA standards anyhow so I guess this will just expedite the purchase.

Hi all,

My this post was very helpful in determining what was causing my 4-6-2 to derail on switches. I have deduced that it is the trailing truck not returning to center after the engine comes out of a turn. My question is how do I correct this? The ground wire doesn't impede movement of the truck but the truck does not move in the slot that the rod with the spring combination sit in after a turn. Would more weight on the truck fix this?

As always your help is greatly appreciated!

Jaggar

Every problem is different.  I have 50 or so engines of all makes and wheel configurations that all work fine most of the time.  Recently I had an issue with the Marx 333 4-6-2 on the Lionel uncoupling section (the ones with the red plastic center). 

The engine would stop and reverse and stop and reverse on the two or three of the sections but not on the 10 to 15 other ones.  I bent on the brass sliding pickup and tried to make it look just like the one on the good working 333 for a day or two.  Finally I noticed one of the driver wheels was loose on the axle and was able to tighten it up by gently hammering it on better.  That improved it and it now works better but still acts up after a few minutes to running.  It has been troubling engine and had a shorted out armature which I replaced.

This Marx 333 front 4 wheel truck also would derail on some 027 curves.  I had banked the curves with about 1/8 in rise on the outside rail.  All other engines never had a problem with these curves for 40 years.  I removed several of the wedges to flatten the curves and that fixed that issue.  I do not think the banking made it possible to go faster around the tight 027 curves anyway.

Another problem was a new to me, Lionel 561 0-8-0 switcher that derailed on several Marx 1590 switches.  I found the edge of the moving rail part of the switch of a couple of them were not real tight against the rail it edged up to and bent it to close the gap.  Again none of the other engines had a problem like that.

A couple years ago I got a like new to me, Williams ABA Santa Fe F 7 diesel set.  It shorted out on many Marx switches.  I found the pick up rollers were too wide causing the shorting out.  I ground a little off the rollers edges that fixed that.  Then the engines would derail on so some track joints and at the hump at three bridges as the track was higher on the bridges ( the metal of the bridge base made the bridges higher than the approach tracks).  I bent the metal tie bases flat on the bridges to lower the track on the bridges and installed thin pieces of aluminum flashing in the gaps at the track pins.  The powered unit would run only in reverse so I reversed the lead to the dc canned motors to let it run in forward only which is fine for me now.

All these issues make my tracks smoother and better for running all the engines.  I find when I drift from my Lionel 242, 2026 and 2035 engines and go for other makes and diesels and 8 wheel configurations operations are not as smooth.  I have had good experiences running Lionel 2046 and 2065 baby Hudson's.  My layout is a switching (as in changing routes not making up train consists) and operating layout with 28 Marx switches and a homemade turn table so it has lots of pit falls to smooth operation.

Charlie

Choo Choo Charlie posted:

Jaggar

Every problem is different.  I have 50 or so engines of all makes and wheel configurations that all work fine most of the time.  Recently I had an issue with the Marx 333 4-6-2 on the Lionel uncoupling section (the ones with the red plastic center). 

The engine would stop and reverse and stop and reverse on the two or three of the sections but not on the 10 to 15 other ones.  I bent on the brass sliding pickup and tried to make it look just like the one on the good working 333 for a day or two.  Finally I noticed one of the driver wheels was loose on the axle and was able to tighten it up by gently hammering it on better.  That improved it and it now works better but still acts up after a few minutes to running.  It has been troubling engine and had a shorted out armature which I replaced.

This Marx 333 front 4 wheel truck also would derail on some 027 curves.  I had banked the curves with a about 1/8 in rise on the outside rail.  All other engines never had an problem with these curves for 40 years.  I removes several of the wedges to flatten the curves and that fixed that issue.  I do not think the banking made it possible to go faster around the tight 027 curves anyway.

Another problem was a new to me Lionel 571 0-8-0 switcher that derailed on several Marx 1590 switches.  I found the edge of the moving rail part of the switch of a couple of them was not real tight against the rail it edged up to and bent it to close the gap.  Again none of the other engines had a problem like that.

A couple years ago I got a like new to me Williams ABA Santa Fe F 7 diesel set.  It shorted out on many Marx switches.  I found the pick up rollers were too wide causing the shorting out.  I ground a little off the rollers edges that fixed that.  Then the engines would derail on so some track joints and at the hump at three bridges as the track was higher on the bridges ( the metal of the bridge base made the bridges higher than the approach tracks).  I bent the metal tie bases flat on the bridges to lower the track on the bridges and installed thin pieces of aluminum flashing in the gaps at the track pins.  The powered unit would run only in reverse so I reversed the lead to the dc canned motors to let it run in forward only which is fine for me now.

All these issues make my tracks smoother and better for running all the engines.

Charlie

Thank you for your insight I have a feeling as I get more experienced your information will be very valuable! I am going to see if maybe lubricating the post will help it move in the slot.

Don't use a finger, but probe the slot for burrs. Edges should be softly rounded to top/bottom; not "sharp". Same for the truck hook/tab, soft edges slide, sharp ones bind.

Maybe bind from/in the blue paint thickness (a slight, even, "run" in the paint where sliding occurs).

Have you.looked at the wheel gauge close? Will flange backsides clear the guide rails well? Is a wheel hopping into the gap though it's rubbing the guide? (wide)

Are the trailing truck wheels of fast angle design? I wonder if a set of flatter treads might be a better fit for the Atlas railhead?

Is the rail gauge ok? Aligned inline across gaps?

Any possibility the down force spring saw heat? Derail, etc..? (heat kills some springs pretty easy)

Adriatic posted:

Don't use a finger, but probe the slot for burrs. Edges should be softly rounded to top/bottom; not "sharp". Same for the truck hook/tab, soft edges slide, sharp ones bind.

Maybe bind from/in the blue paint thickness (a slight, even, "run" in the paint where sliding occurs).

Have you.looked at the wheel gauge close? Will flange backsides clear the guide rails well? Is a wheel hopping into the gap though it's rubbing the guide? (wide)

Are the trailing truck wheels of fast angle design? I wonder if a set of flatter treads might be a better fit for the Atlas railhead?

Is the rail gauge ok? Aligned inline across gaps?

Any possibility the down force spring saw heat? Derail, etc..? (heat kills some springs pretty easy)

I bought the locomotive off a member here and the board was dead on arival so I assume that there is a possibility for the spring to have seen some heat. The wheels clear the guide on the frog no problem as far as I can tell. Visually inspecting the trailing trucks slot I don't see any imperfections in the paint or burrs. When I rubbed my finger over the slot (sorry I couldn't come up with a better way haha) It definitely wasn't buttery smooth around the edges but it was uniformly like that the entire slot and not sharp either.

The wheel is hopping on the plastic tab that atlas fixes to the moving part of the rail (the part the switch machine interacts with)

I used Lionel's multipurpose lubricant I had laying around (#2927-10) on both slots (the slot on the chassis, and the slot on the trailing truck) and now even though the post still doesn't reset back to center on straights it no longer "hops" on the tabs and is running normally again. So the grease seemed to solve the binding issue. Would adding weight to the trailing truck further help it, like replacing the spring, or adding stick on tire weights?