Walthers Loco Doesn't Like Bachmann Turnouts

[keesu]

Hello, Folks

I was wondering if any of you have ever come across the problem of certain locomotives cutting out on Bachmann turnouts.  I have a Walthers Proto F3 A/B locomotive that runs fine except when it crosses certain turnouts, not all of them, and usually at slow speeds.  The loco tends to lose power and lurch, the lights and sounds go off, but then it regains power and continues to move. 

I have three other locos that perform perfectly, so I know it's not the turnouts but something about the locomotive.  I returned the first one I bought, thinking that the loco was the problem, but the replacement does the same thing, although not as much as the previous one. 

If you have any insights or suggestions, I'd certain appreciate them.

Thanks,

Keith

[DAVE2744]

Keesu - I have a F3 Proto, DCCw/sound, I would assume it shares the same guts as the F7. New model 2014.  I think you are correct in that the B'mann switches are not the problem.  The Proto trucks have very little clearance and do not move, "wobble" if you will, much at all.  They actually were hitting the side steps of the shell and the rear truck was touching the coupler cast in place mounting.  It would stall out on my Peco switches all the time.  Check yours out.  Dave

[Len]

I'm not sure why, but I find the Proto locos are a lot happier with powered frogs. So I don't have a lot of Proto locos.

Len

[keesu]

Keesu - I have a F3 Proto, DCCw/sound, I would assume it shares the same guts as the F7. New model 2014.  I think you are correct in that the B'mann switches are not the problem.  The Proto trucks have very little clearance and do not move, "wobble" if you will, much at all.  They actually were hitting the side steps of the shell and the rear truck was touching the coupler cast in place mounting.  It would stall out on my Peco switches all the time.  Check yours out.  Dave

Yep, Dave, I noticed the same thing when I compared the clearance to that of my other locomotives.  It's funny, though, that today when I ran the loco again, I didn't have the same problem, just a very slight hesitation at one point, but that happened only once.  It's also interesting that it doesn't do this on every turnout, just a couple of them. 

I don't understand why it seemed to lose power but continue to run and then come back to life.  I'll admit up front that I'm an rank amateur when it comes to things like this, but I have enough experience to employ the process of elimination.  I envy your command of terminology!

In any case, it's good to know, in a strange way, that I'm not the only one in this situation. Thanks so much for the input.

Keith

[keesu]

I'm not sure why, but I find the Proto locos are a lot happier with powered frogs. So I don't have a lot of Proto locos.

Len

Len,

I think I'm starting to agree with you about Proto locos.  I have back ordered the Capitol Limited set but am having second thoughts if I have to go through this frustration again.   As I said in another post, though, the loco worked almost perfectly today, the moody devil.  Thanks for your help.

Keith

[electrical whiz kid]

For what it is worth:
You new guys should take some time to learn the mechanics and tendencies commensurate with this hobby.  I say this not so much because there is required reading, or anything like that, but so that problems like this could possibly be solved by taking a minute and looking in the right place for the right thing.  From what I take from this, some of the older "vets" here could stand to do likewise.  Learning about the hobby from the mechanical/electrical standpoint is essential for the ultimate goal we are all setting for ourselves.
Rich
SGT C.

[Joe Satnik]

Hi, Keith,

There is a possibilty that something is shorting out, but more than likely it is poor power pick-up by your loco, causing an "open".

Non-powered frog turnouts rely on the (frog-side) wheels that are not over the frog to do a good job of picking up power.

If your wheelbase is shorter than the frog, there will be a moment when all wheels are over the non-powered (dead) frog, causing a stall or hesitation.

This usually happens on higher numbered turnouts (which naturally have longer frogs).

Check your loco for good power pick-up:

1.) Turn the loco over in a padded cradle.

2.) Use an Ohm-meter (one of the functions of a Digital Multi-Meter, or DMM) set to its lowest Ohm range

to check for continuity between all pick-up wheels on the same side of the loco.  

Wheel-to-wheel resistance should read near zero Ohms (less than 2 Ohms?).

3.) Repeat for the pick-up wheels on the other side of the loco.

Dirty wheels can cause these problems, too, so clean your wheels.

Another possibility, some turnouts have rivets holding (and transferring power to) the point rail that can loosen and lose continuity over time.

You could disconnect your power pack from the rails and check your point rail continuity with your Ohm-meter.  

Hope this helps.  

Sincerely,

Joe Satnik

Edit: added Italics for grammar and clarification

[Desertdweller]

It may be helpful to remove the body shell and run your loco through the turnout.  This will at least tell you if interference between the truck and some part of the body is causing the problem.  If side steps are interfering with truck swing, you can thin the steps with a mill file or gently bend them outward.

Les

[jward]

I don't understand why it seemed to lose power but continue to run and then come back to life.  I'll admit up front that I'm an rank amateur when it comes to things like this, but I have enough experience to employ the process of elimination. 
Keith

you are running this loco on dc right?

proto locos, like the athearns they are based on, have flywheels on the motor. these enable the locomotive to "coast" over some dead spots, and also simulate somewhat the sluggish response of a real locomotive. this would be why your loco seems to lose power but keep running. the momentum of the flywheel is carrying it forward.

[keesu]

I don't understand why it seemed to lose power but continue to run and then come back to life.  I'll admit up front that I'm an rank amateur when it comes to things like this, but I have enough experience to employ the process of elimination. 
Keith

you are running this loco on dc right?

proto locos, like the athearns they are based on, have flywheels on the motor. these enable the locomotive to "coast" over some dead spots, and also simulate somewhat the sluggish response of a real locomotive. this would be why your loco seems to lose power but keep running. the momentum of the flywheel is carrying it forward.

I think I forgot to mention that I'm running the loco on DCC and the turnouts are also DCC.  I see what you mean about the fly wheel and momentum.  Last night I ran the loco at a very slow speed over every turnout and noticed that it stopped and restarted over almost every one of them.  I ran my other locos the same way without any trouble. 

[keesu]

Hi, Keith,

There is a possibilty that something is shorting out, but more than likely it is poor power pick-up by your loco, causing an "open".

Non-powered frog turnouts rely on the (frog-side) wheels that are not over the frog to do a good job of picking up power.

If your wheelbase is shorter than the frog, there will be a moment when all wheels are over the non-powered (dead) frog, causing a stall or hesitation.

This usually happens on higher numbered turnouts (which naturally have longer frogs).

Check your loco for good power pick-up:

1.) Turn the loco over in a padded cradle.

2.) Use an Ohm-meter (one of the functions of a Digital Multi-Meter, or DMM) set to its lowest Ohm range

to check for continuity between all pick-up wheels on the same side of the loco.  

Wheel-to-wheel resistance should read near zero Ohms (less than 2 Ohms?).

3.) Repeat for the pick-up wheels on the other side of the loco.

Dirty wheels can cause these problems, too, so clean your wheels.

Another possibility, some turnouts have rivets holding (and transferring power to) the point rail that can loosen and lose continuity over time.

You could disconnect your power pack from the rails and check your point rail continuity with your Ohm-meter.  

Hope this helps.  

Sincerely,

Joe Satnik

Edit: added Italics for grammar and clarification

Thanks for the suggestions, Joe.  I forgot to mention that the turnouts and loco are both DCC, if that makes any difference.  I noticed that the loco stalls and restarts precisely at the point at which the wheels are over the frog and the point blades. 

I'm wondering if I'd find the same problem with an Athearn F3, which I considering buying after I sell the Walthers.

Keith

[DAVE2744]

Keesu - Here is something to try to isolate your problem.  Run the loco as you did, very slowly, and let it stall.  Do nothing more at that point. Do not change any control inputs, leave the throttle as is.  Take a straightened paper clip or a very fine screwdriver and lightly slide it along the same rail as the frog is on, up to the opposite wheels on that same rail.  When the clip touches the opposite wheels ( on the same rail as the frog ), I'll bet the loco fires right up.  Remember, the right side wheels of the front and rear truck should be picking up power together on these models. Same goes for the left side. You might have a bad wire connection to the truck that was not on the frog. Also, I have noticed that different materials used for the wheel rims plays a huge part in the quality of the electrical transfer from rail to wheel.  I actually find most of my B'mann locos are much better at this, and I own several different brands of locos.  The Proto locos are fine runners, so don"t give up too soon.  Good luck,  Dave

[keesu]

Keesu - Here is something to try to isolate your problem.  Run the loco as you did, very slowly, and let it stall.  Do nothing more at that point. Do not change any control inputs, leave the throttle as is.  Take a straightened paper clip or a very fine screwdriver and lightly slide it along the same rail as the frog is on, up to the opposite wheels on that same rail.  When the clip touches the opposite wheels ( on the same rail as the frog ), I'll bet the loco fires right up.  Remember, the right side wheels of the front and rear truck should be picking up power together on these models. Same goes for the left side. You might have a bad wire connection to the truck that was not on the frog. Also, I have noticed that different materials used for the wheel rims plays a huge part in the quality of the electrical transfer from rail to wheel.  I actually find most of my B'mann locos are much better at this, and I own several different brands of locos.  The Proto locos are fine runners, so don"t give up too soon.  Good luck,  Dave

Hi, Dave

Thanks for the suggestion.  The problem is that the loco doesn't completely stall; it just slows down and then stops very briefly, then the lights go off and sound resumes when the loco starts moving again.  I think I'm ready to give up.

I do have one more question I'm hoping you or someone else can answer.  On the underside of each Bachmann DCC turnout and crossover, there's a little wire with a plug on the end that's not hooked up.  There's a place to plug it in right under the frog.  I've never plugged any of them in because they arrive in the package unplugged.  Today, I plugged in the wire on one of the turnouts and the loco didn't stall after that.  When I plugged it in on the large crossover--a #6 left crossover, the loco completely stalled and wouldn't run through the crossover until I umplugged that little wire.  The same thing happened on a #6 right turnout. 

I guess my question is this:  What function does that little wire serve?

Thanks,

Keith

[jbrock27]

Keith, do you have the ability to temporarily switch the loco to run on DC, run it, and see if it behaves the same way?  That may help narrow down where the problem is.

If you search the forum, you should find info on what that wire does.

[DAVE2744]

Hello again Keesu, I'm not familiar with the type of switches you have.  If the frog of the switch is metal, my guess is that the wire is used for power routing ( frog takes on correct ( same ) power as the moveable point rail that is aligned with the frog). I'm surprised ( ha ha ) that there was no documentation in the packaging on how to use that wire. 
Even though you have a situation with the switch, I think you still have a problem with the loco.  The wheelbase is long enough that the other set of trucks, the one not on the frog, should have been supplying the alternate route for power to loco. Test your loco by putting a very thin piece of paper under both wheels on one side of a truck.  You should not have any interruption in power.  Repeat for all four sides. If you do lose power, the truck wheels at the other end of the loco, same side,  is not passing electricity, ( poor pickup from wheels, bad wire connection at truck, bad wire connection at pc board ). Just think of all the new knowledge you will have gained when you work through all this.  It will be rewarding,  Dave