MTH GP38-2 with "SCALE WHEELS"?

Lay the diesel on it's side and power it from each set of trucks, one at a time. This makes sure that both are picking up power and from all the wires. Sometimes, it's one engine that makes a layout need powered frogs. It will be worth it, as you acquire more "shorter" wheelbased engines.

I have seen where the wheels were swapped incorrectly, causing this issue.

Shorter wheelbase, fewer wheels.

I forgot to mention that I'm using Atlas t/os but figured sort of blindly,if no other diesels had the issue why should this 1.

Thank you will give this a try. The smoke unit must be on & it caused serious sinus trouble thought I was going to die this morning almost went to ER. Will let sinuses clear,just wondered what I'm facing. To power t/os,can I run 1 wire from small round turnout tab on outside of tie across from turnout frog,to positive wire? The hotwire I mean? I'm lost on wiring. I know in HO how to block wire but that's all.

Thanks again.

Al Hummel

No, because that would power the frog for one direction of throw. It needs to swap when thrown in the other.

So it would need to be controlled by something like a tortoise machine.

Engineer Joe,

To power frogs,I have to wire 2 hot wires to the frog,1 from the frog to each hot leg of the turnout? I'm not familiar with wiring never had this problem in HO,everything was prewired. Never had stalling in dead frogs either.

I think this is an engine problem as no other diesels had it. So to check,I lay diesel on its side then take a hot wire to each truck to see if wheels spin? Does it matter which wheel-are they the same set of wheels on each truck,in other words with the diesel on its side,will it be the 2 wheels facing me on each truck? As you can tell,I'm not electrically knowledgeable.

Thank you,

Al

well the simplest way I think, is to power the engine by each axle one at a time and see what works.

No, you can't run both track wires directly to the frog or you'll create a dead short. There needs to be something that controls which path powers the frog when the switch is thrown.

BTW, yes it can be just one engine that shows the problem. It does not mean that the engine causing the problem, has a problem. When a short wheel based or engine with the power points close to the middle runs, it can find the places in the layout where there's larger gaps in power supply.

 Another way to solve, is to have a tethered connection to another trailing engine or car to serve as a power bridge.

 Enginner Joe,

Will a lash up help?

Al

Al,

Here's a fairly simple way to manually throw the switch and flip frog polarity at the same time using a slider switch from Radio Shack etc. You can also add a throw rod to the plastic switch knob that connects to the tie rod with a piece of music wire. Lots of stuff online about this. 

A more complex but more reliable solution involves making flexible wire feeders/jumpers from the closure rails to the switch points. With both of these upgrades done, you have 100% continuous power to both rails throughout the entire turnout in all directions. Often called "DCC friendly", but works well with DC as well. 

HTH

Pete

Alan Hummel posted:

 Enginner Joe,

Will a lash up help?

Al

no, probably make things worse for U! The engine is not connected electrically with any tethers. So in a lash-up if it stalls, the others will try and overcome the load while the remote struggles to talk with an engine that won't respond. That makes all engines in the lash-up, out of control.

 The engine would need to be electrically connected to another engine, making it in essence, a longer engine!

Have you tested the wheels yet? Maybe one truck has a bad wire connection?

I just found,it's not the turnouts with the dead frogs-I can touch the diesel with the tip of my fingure or touch the track & the diesel instantly moves or at least revs. I don't mean a hard touch either as in shoving the diesel,just the touch of a hair practically will bring the diesel back to life. Sometimes a snail's crawl keeps the engine moving more than a medium or fast pace. I'm the dumbest guy when it comes to electricity,but this seems to indicate an electrical problem with the diesel. I NEVER saw ANYTHING SO TOUCHY! I can't expain how the slightest touch,a hair's thickness will get the diesel to revive electrically,then move. I think MTH needs a "go" at this.(?)

All opinions are welcome & I thank all in advance.

Al Hummel

when the wheels get removed, it's important that they get reseated correctly. Of course there maybe a broken wire or wire shorting to the frame. Just touching the loco doesn't figure out the problem totally. it does help sort things out. I don't think it's any wide spread problem that needs MTH's direct attention. Unless you mean you're sending it to them for fixing?

 I have a ton of their engines without issues.

Alan,

I think Joe is in the right track with the trucks, contacts and wheels on the trucks of that loco.  IMO, If the loco doesn't exhibit this behavior on regular track, then it's likely something in the pickup especially if you aren't currently powering your frogs, and the frog is completed isolated.

Alan,

What you are describing is a classic pickup issue.  Either there is a broken pickup wire from one of the trucks to the circuit board, or since these are not individually sprung axles then  the wheels may not all be setting on rails and actually slightly lifted, even a separation of the width of a human hair off the rails, and no contact will be made and the loco will stop.  Push the truck side frame ever so slightly and now the wheels make contact once again and the loco moves. 

 A simple test you can do for the broken wire or pickup wiper not touching is put only one truck at a time on the rails (the opposite truck should be not touching the rails (place a piece of paper under that truck to insulate it from the rails), now increase the throttle, the loco should move under its own power.  Now swap the piece of paper under the other truck, and once again increase the throttle, the loco should move again.  If the loco does not move in one of the two tests, then there is most likely an issue (probably a broken wire from the wheel pickup wipers to the circuit board or the pickup wipers themselves are not making good contact with the wheels in that truck that is not on the piece of paper.   

I have seen issues in past with an Atlas loco (construction is similar to MTH) where the track pickup wire leading from the truck to the cicuit board was placed inside a screw eyelet crimp style spade connector but for some reason was not crimped at the factory.  I just put a little solder on the connector at the crimp location and that solved my pickup issue.  Basically, one truck was not getting power to the circuit board so the loco pickup was relying on just one truck and therefore very, very sensitive to even the slightest undulation in the track, dead frog, or even dirty spots on the track, causing the loco to frequently stall.  

Scott K.

Austin, TX

Good Day,

I have experience many times in the past with SD70ACe's that the wires connecting to the trucks were not secure and many times had a lose connection. This required a more secure fit.

...........and on several MTH engines I had in the past...........the screws were missing to secure the electrical pickup wire to the truck.

Regards,

Swafford

SCOTT KAY,

I performed the "paper test" like you said & the non cab truck is the supposed problem as the cab truck runs across the paper with no problem.

Now that the problem is better identified,what do I do as I know nothing about wiring.

This was a 3rail GP38-2 that I had Mr. Muffin out if Carmel,In,close to Indianapolis,change over to 2rail trucks. I guess I could send it back there,but he seems awfully busy. Straight track is no issue on performance just the turnouts. Oddly,the slower the diesel travels,the better it does,but in an issue like this,I'm guessing that everything has a better chance to line up where's at higher speeds it doesn't fall in line as good. Something else I noticed which could have little or no bearing,is that when the cab end is run face into the "tunout" track there's more stalling than if the non cab side is run into the leg of the turnout.(?)

You think MTH is my best bet? I have an unknown man that loves working on Lionel but MTH is not his cup of tea,so don't know how helpful he would be.

Thank you.

Al Hummel

Swafford posted:

Good Day,

I have experience many times in the past with SD70ACe's that the wires connecting to the trucks were not secure and many times had a lose connection. This required a more secure fit.

...........and on several MTH engines I had in the past...........the screws were missing to secure the electrical pickup wire to the truck.

Regards,

Swafford

I have to admit Frank, that the MTH SD70M-2 EMD demo you got had more than one problem. It had a weak board, shorting wire from missing insulator inside the truck, and a rubbing wire, are just what I remember!

 I can't say though, whether the board was damaged from the shorting inside the truck or a bad component. I put all the guts into another engine. To this day it still runs. You really got a bad one!!! 

Hi Joe,

WOW, I did not know there were that many issues with the engine. Sorry.  I love that EMD Demo color scheme though.

Regards,

Frank

Engineere Joe&Frank:

Geepers! With that many problems with MTH,I'm thinking HO is the place to stay! Is this common place with their diesels? I got 2 GP 40's due in June. More problems on the way?

Al Hummel

Well you narrowed down what's causing the issue. Now to see why. Bad wheel install? broken wire? With your experience, I would recommend having a tech look at it. Explaining what tests you've done should help.

 No, there's no widespread MTH problem. I have a large number of their engines. I have bought problem ones to learn from. I've only ever had one total failure. I believe that G scale engine was dropped or crashed. After a total rebuild, even that engine now runs fine.

 Disclaimer: I have stayed at many high end hotels and I have met Mike Wolf in person. So that makes me a self proclaimed almost tech expert!!

Now if I could just keep my RR's running!!

No Frank, that was a great engine that must have been built while someone was texting! It just needed extra love. I still have it and cherish it myself. It took until recently for me to get the others that I sought. The first white demo and the CSX versions.

 All the other engines I got from you ran perfect and continue still.

I do miss those Atlas CSX hoppers and would have bought them back! Rats.

I have a bunch of them and don't have issues, either in 2-rail or 3-rail mode. One thing I suspect, though, is that they pick up current off the axles rather than the wheels which makes inspection an issue with the plunger/wipers. Wheel wipers are easier to access/inspect. I have one locomotive with quite a bit of use (one of my U25B's, the first two I bought back in 2009) that occasionally "stutters" leading me to believe that one or more of the contact plungers might not be making good contact.

I've personally seen issues with the wires leading from the trucks to the superstructure. sometimes they're not properly installed and the chassis scrapes through the insulation causing a short. This also impacts the hi-rail versions (I fixed one for a club member a couple of months ago).