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Almost all the steam and diesel power in my Run Room is MTH.  The performance of the MTH engines with Proto-Scale 3-2T 3-Rail/2-Rail Conversion capibilities is unacceptable and I won't be buying those engines.

 

After running my "new" #20-3383-1 (engineering edition) I discovered it will not creap through my Ross switches (Ross 220 #8 switch and Ross 101  11 degree switch).  I must run it through fast like I used to run my postwar engines (so I could blow the whistle).

 

Thorough investigation showed that the wipers on the engine rear axle are very fragile, and all wheels are insulated from the engine and tender housings causing a problem with conductivity with the outside rails.  The engine has only 3 wheels wired to act as common to the outside rails and one of those wheels has a rubber tire.

 

After extensive improvements to my 20-3383-1  2-3-1 Pacific Steam Engine, the engine is on probation.  See solutions here  MTH 20-3383-1 2-3-1 Pacific Steam Engine or  http://www.slsprr.net/features...0Pacific%20Steam.htm

Last edited by Susan Deats
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MTH 3/2 steam locomotives are set up like 2-rail locomotives (they kinda have to be to work in 2-rail. Basically, the wheelsets are all fully insulated. What's happening is you're losing your ground. The way around that on turnouts is to put a connection to common on the closure rails of your turnouts, especially larger ones, but to prevent shorting from the pickup rollers, these connections will have to be tied to a relay (or Tortoise motor contacts.) We had to do that on a #8 curved turnout. Not really hard to do.

 

What kind of turnout motors are you using?

Originally Posted by gftiv:

Why should the 3 railers have to rework their layout to accommodate the 2R/3R engines?

Most of us probably don't - for example I use only Fastrack switches even though I otherwise have all Atlas track - so I don't have these or any other problems sense they are bulletproof switches. 

 

So, I don't have the specific problem Susan Deats has but I had problems with them.  have noticed that MTH 2R/3R engines seem to be weak on picking up power from the outer rails as compared to toy loco made only for 3R.  I've had trouble with them quickly and firmly operating some block activated accessories, etc.  although so far they have activated the switches' auto-reversing features well enough. 

Almost all the steam and diesel power in my Run Room is MTH.  The performance of the MTH engines with Proto-Scale 3-2T 3-Rail/2-Rail Conversion capibilities is unacceptable and I won't be buying those engines.

 

Even some of the straight 3 rail engines will stall on a Ross #8 switch(a thing of beauty) without special wiring as alluded to. However I certainly agree  you.

 

We're not buying  anymore either. Why would you put wipers on a 3 rail engine to pick up the common, Rail-king seems a better deal to me.

 

I don't think turning a set of wheels around in the  tender would help much??

 

I don't have a engine and continuity meter handy.

gunrunnerjohn, there are 12 insulated wheels on my steam engine.  I didn't pull the wheels and I made some ASSumptions. 

 

The wipers on the rear axle are wired to the common bundle (I assume that is in contact with one rear wheel).

 

The driver wheels (one has a rubber tire) on one side appear to have wired contacts to wheel hubs that connect to the common bundle.  The front 4 wheels have no way to connect to the common wire.  I have no idea how the engine picks up positive and negative power when running on 2 rail.  One contact is obviously the common wire bundle.  There is no electrical contact/ground to the engine housing.

 

See instruction sheet page 9 for photo of wheels

http://mthtrains.com/sites/def...ction/20st15359i.pdf

I'd say add brass wipers and flex wire to the engines lead, trailing and drive wheels to better accomodate the ground p/u needs...attach all those to the main chassis via a single or mutiple leads- the removable center p/u should be well insulated and be fine on its own.

I always wondered how well a convertible engine...2r/3r...would adapt between venues...seems my question is answered.

I just saw some fine flex wire the other day and am struggling to remember just where that was, but there's other wire options too so long as you keep it thin and very flexible to keep lead and trailing truck binding at bay because of the added wire.

Originally Posted by gftiv:

Why should the 3 railers have to rework their layout to accommodate the 2R/3R engines?

You have to rework your layout so that all of the engines you choose to run on it work. I had to re-wire the Ross #8 curved turnout because short-wheelbase 3-rail engines or those with only two pickup rollers closely spaced (Atlas SW's, early Lionel Geeps, early MTH Geeps, small Box Cabs, etc.) would stall at low speed and lose their ground connections.

 

At some point in time, you'll have to rework something on your infrastructure to support a new purchase, even if you don't come anywhere near a 3/2 locomotive.

 

Clem:

 

I think the diesels are wired differently from steam and use double-insulated wheelsets. Steam gets complicated because there are so many moving parts that may directly or indirectly contact the locomotive frame, even if you double-insulated the wheelsets.

Originally Posted by AGHRMatt:
Originally Posted by gftiv:

Why should the 3 railers have to rework their layout to accommodate the 2R/3R engines?

You have to rework your layout so that all of the engines you choose to run on it work. I had to re-wire the Ross *3 curved turnout because short-wheelbase 3-rail engines or those with only two pickup rollers closely spaced (Atlas SW's, early Lionel Geeps, early MTH Geeps, small Box Cabs, etc.) would stall at low speed and lose their ground connections.

 

At some point in time, you'll have to rework something on your infrastructure to support a new purchase, even if you don't come anywhere near a 3/2 locomotive.

 

Clem:

 

I think the diesels are wired differently from steam and use double-insulated wheelsets. Steam gets complicated because there are so many moving parts that may directly or indirectly contact the locomotive frame, even if you double-insulated the wheelsets.

Hi Matt

Your probably correct. My thinking was with three axles the center wheels sometimes don't touch the rails and a traction tire on one wheel only leaves one wheel for contact. Just a thought.

Oh by the way I could use three rail wheelset's.

Clem  

I only have one 3/2 steam engine. PS&N Russian decapod.  Just some information about how it is assemble to achieve the 3/2 configuration.   Keep in mind three rail allows for common from both outside rails. 
Locomotive is split down the middle each left wheel is electrically isolated from the right wheel including the pilot. All left wheels are common and show continuity through to the frame.  All right wheels are isolated. 

The tender is designed for two rail pickup with the (4) axles as pickup.  (2) Axles, front truck, are power right rail. The front axles are isolated from the frame with plastic inserts in both side frames. The (2) axles, rear truck, are common left rail with the right wheels isolated. One of the truck side frames has brass inserts for the axle. Common pick-up through the truck frame and the frame of the tender.
Three rail pick-up center rail is via the two installed third rail pick ups.  A wiper assembly was add to the front tender truck to increase outside rail pickup via the other rail.  A couple of pictures.
Rear tender truck notice the brass inserts in the truck side frame. the wheels, bottom of the picture, are isolated from the axle.   Common pick-up (left) (Two rail).

The front tender truck is designed, (two rail), for pick up of power on the (right) rail. The isolated wipers are added to allow for Common pick-up via the (right) rail when the third rail pick-ups are added. Therefore you have Common from either the left or right outside rail.  
Noted difference front truck is the axle wipers and the plastic axle bearings.
Plastic axle bearings are both sides isolating the axle from the truck frame.

Remove the thirdrail pick-ups, leave the wiper, switch the three/two rail switch and it should be ready for two rail operation.

The wiper assembly on this axle appears to allow for common pick-up from both outside rails when the third rail pick-ups are added. Tender switch in the three rail position.

The Tender if all wheel/axles are assembled properly with the wipers should allow for common pick-up off both outside rails.  Locomotive only allows for one side common rail pick-up. 

 

Susan should check the tender for the brass insert bearings that allows for the two outside rail pick-up as it moves through a switch.  If all axles are have plastic bearings the only outside rail pick-up is via the wipers shown.  Limited outside rail pick-up as she indicated.   I could be wrong and often. 

 

Best wishes with your project.

Mike.    

Last edited by Mike CT

This is a very interesting thread, it sounds as if the simple fix that GN John is talking about could be done at the 3R to 2R switch. Do all such engines from MTH have this switch?

 

This is one of the reasons why I love RK imperial products. I doubt if the 2-rail market would stand for anything less then Premier standars so I guess I'm safe.

I do not have any steam with the 3/2 capability, however, I did have incessant issues with two geeps.  The frustration with resulted in a 3/2 switchectomy!  They run fine now.

 

Personally I believe by trying to make these engines all things to all people, they are becoming more tempermental.  I concur that the simple RailKing offerings are much more robust.  There was an initial problem with contacts in the trucks and a small brass piece was offered if pickup of power was insuffiecient.  It wasn't, however, well publicized.  FWIW

Dunno about all the details above, but my big 3/2 ATSF 3463 Hudson would stop in

my GG switches when moving slowly. I discovered that some of the wipers were simply

not touching the axles. I adjusted/bent them and the 3463 is actually one of

the most electrically sure-footed locos that I have ever seen. Never blinks.

Hi D500, you would be surprised at how many tracking problems I have fixed by adjusting the ballast of a switch or a minor adjustment of the pick-up rollers.

 

I had an old Williams engine, an FM that would not take an O-72 turn. It turned out to be a power wire was a little to short to allow the motor to move through a turn, or a switch. Just goes to show ya, it's not always a complex fix to our problems. Sometimes it just takes a close look.

Hi All,

 

Sometime back I posted a problem with my MTH Railking steam proto 3, not sure

of the item # at the present, I am having issues when the engine is crawling through an Atlas switch, it just shuts down. When you push the engine past that point, it will startup and run. I was told to reposition the pickup rollers  (turn them inward)to correct this which has not been done as of yet. The switch does have a power and common drop.

I am running 3 rail DCS. Is this the same issue as what is noted in this thread?

Mike CT, thank you very much for the comprehensive 2 3 rail information and excellent photos.  My engine is not a project any more. I hadn't planned on it being one of my main runners.  It looks great and it's fun to have.

 

Since my Run Room theme is a Texas South Plains Railroad, that engine was imported by a Texas rancher oil man while he was on vacation in Europe.  The rancher really liked the engineering model.  He even hired the engineer and conductor to come home with the engine.  Engineer and conductor speak no english.  That steam engine will pull stock cars and oil tankers when needed and it will be running fast through the yard until some of the coating wears off the wheels.

Do you think they are trying to do too much with a single engine? Seems to me they should have separate products for 3 rail and 2 rail. I think at one time MTH made a limited number of 2 rail engines.

 

Also, one of the suggestions in the Tips and Tricks publication from Kalmbach a few years ago had to do with insulating one of the outside rails to allow for future accessory activation. I did that on my layout to the outside third rail to allow for the installation of crossing gates ect.

 

My guess is that could cause a problem if only one of the outside rails of one of these MTH engines can pick up the common or ground.

 

For what it's worth, concerning Atlas O switches, there is definitely a "dead spot" in EVERY Atlas switch. This is the gap between the center rail and the corresponding twin-rail hot section near the point pivot area (I know I'm not describing it clearly). Anyway, the spacing of pick-up rollers on EVERY SINGLE 3-Rail locomotive, steam or diesel, or electric, MUST have the pick-up rollers farther apart than this gap (dead spot) in every switch. Thus, some locomotives, with pick-up rollers closer together than about 4 or 4 1/2 inches, will stop dead!

 

I have an MTH New York Central Mohawk that I had to add a third pick-up roller on the tender, in order to span the gaps in my Atlas #5 switches. No more problems now. 

Hi

I have a steam engine MTH 20-3313-1 and it is a 2 to 3 rail type with the same stalling problem.

The locomotive is build with no power pick up and a rear trailling wheel truck with a wiper toutching the axels. The wiper is fixed on an insulated  bracket. picture1

 The right wheel are not insulated and they are in contact with the right rail (probably the power pick for two rail)

 

Picture 2 is the two to tree rail tender with the wiper on the front truck

Hope the picture will give you some clue 

John

tender whiper

Attachments

Images (2)
  • Locomotive rear trailling wheel with wiper
  • tender whiper
Last edited by SnowmanJohn

IMO There is a very good posibility that the 3/2 locomotives/units can be produced at the cost of either a 3 rail or 2 rail locomotive, and eliminates the need to set up a special production for limited two rail units.  Hobbyist are either two rail or three rail, not a lot of change from one to the other. IMO  

 

Usually switch (turnout) continuity problems are with the center rail. It's unusual to see an outside rail problem, but the 3/2 has the ability with it's isolated wheels to create that problem.  The Decapod that I pictured has been a solid, trouble free runner. 

 

I've also done an Atlas 6924 relay upgrade to my layout that has solve dead spot problems. Surprisingly, Jack, my Weaver E8's with pick-up rollers 14" apart could find back to back turnout dead spots. 

 

Interesting discussion

Mike  

Last edited by Mike CT

Odd. I have an ATSF 3463 3/2 Hudson that was having exactly the same problems with

my GG switches. I suspected something complicated, but after looking at the wipers

I saw that a couple of them were not touching their axles. I gently bent them and this 

4-6-4 will sail slowly through multiple GG switches (old and new styles,

with no special wiring) with nary a flicker. 

 

I know that you've been through all this, but the 4-6-4's AC common-pickup arrangements seem well-designed - and my Chapelon 3-2-1 has never had a pickup issue.

 

GG and Ross (I have a few) switches are pretty similar, of course. Strange.

I bought a MTH Hudson 20-3313-1 used and I have the same stalling problem than your beautiful Pacific locomotive.

 

(The broken wipers were repaired with very little improvement.)

 

The ground strap(parts name) on the locomotive rear trailling truck is there for power feed (+) from the right side track when in two rail mode

 

To be sure compare the two wheels at the end of the axel. The left wheel is fitted with a plastic insulating bushing.The right wheel is straight mounted on the axel and conduct power.

 

My locomotive is built for two rails operation and then be switch in tree rails mode trought the 2 - 3 rails switch. 

 

John

Last edited by SnowmanJohn

I have the painted version on the bench for a repair.  The 2R-3R units do route both wheel sides to black power wire or Outside rails when in the 3R position.  Only when the 2R-3R switch is in the 2R poisition does the wheel isolation come into play.

 

For this unit, the rear truck left wheels are connected to the tender chassis via metal bushings and a gray wire is routed to the polarity switch.  There also is a gray wire with screw into the tender frame connected via wire nut.

 

The right tender wheels on the front truck are linked to the polarity switch via the wiper.  They also are connected to the engine right wheels via harness.  One issue is the blackened axle.

 

When the 3R switch is in 3R, the brown wire bringing roller power from the engine (and tender if equiped) goes directly to the PS-2 3V board red wire position.

 

The polarity switch (depending on which position) routes either the left or right wheels to the 3R-2R switch an directs it to the black 7pin connection.

 

The polarity switch sends the other wheel set to the 7pin ground connection via a direct connection from the polarity switch.

 

The main point being that when in 3R both left and right wheels from the tender and engine go to the outside rail position for board power.

 

If an engine is having problems then one of the switches, pickup points, tether wires, draw bar ground may be having issues.   G

 

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