# Weird problem with engines that have 6-wheel trucks



## [email protected] (Apr 29, 2016)

Hi Guys,
My layout has been "tracked" and wired.....about 200 feet of track. All my engines that have 4-wheel trucks, like RS-3's and RS-1's, run perfectly, even at full throttle....I should mention that I'm using old-fashioned DC technology with Aristo-Craft walk-around radio throttles. When I place an engine with 6-wheel trucks, like a DL109, they start to move and then I hear a click in my Aristo-Craft receiver, indicating there is a temporary short, then the engine moves a little further, about an inch or two and shorts out again. If I start the engine very, very slowly and power it up ever so gently, it doesn't short.

I've checked the wheel spacing on the DL109 and it is fine. I've been in this hobby for over 25 years and have had 3 DC layouts, all using the Aristo-Craft throttles and this has never happened before.

Does anybody have an idea as to what is happening?

Thanks in advance for any ideas you can offer.

Mondo


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## DonR (Oct 18, 2012)

Maybe someone who has used the Aristo controller
would have more pertinent information. I don't
know anything about it.

However, two things come to mind. Do your
6 wheel truck locos draw appreciably more power
than your smaller locos? A multimeter set to amps in series
with one track lead from the power pack would
tell you. Does the Aristo breaker have a sensitivity
control?

I found this discussion thread on line. It may help.

http://cs.trains.com/mrr/f/744/t/272513.aspx

You didn't describe the track situation where the
loco shorts. Was it a straight away, serious curve,
turnout or the start of an elevation?

Don


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## [email protected] (Apr 29, 2016)

DonR said:


> Maybe someone who has used the Aristo controller
> would have more pertinent information. I don't
> know anything about it.
> 
> ...



Hello Don,
First of all, thank you for considering my question. To answer a couple of your questions.

The short occurs both on straight and curved track. My curves are wide anyway and have easements built in, so I don't think that is the problem.

The Aristo-Craft controller does not have a sensitivity control.

I'm not sure I understand your suggestion to use a multimeter, which I have. Could you clarify?

Thank you again,
Mondo


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## D&J Railroad (Oct 4, 2013)

I used the Aristo Craft throttles before I went to DCC.
Pretty much the same as a power pack throttle.
If your B trucks work fine, anything else should too. The AC throttle is merely running a radio control pack that is between your power source and the track.
I would look at the loco wheels to see if by chance they are shifting and shorting out on the chassis of the loco.


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## DonR (Oct 18, 2012)

D&J is right. Your loco wheels could somehow
be shorting to the frame...or there could be a
loose or exposed conductor from the wheel
pickups that is shorting.

To check loco amp draw:
Your multimeter has a setting to measure amp draw.
Set the meter to AMPS.
(To use it, depending on the design of your meter,
you may have to move your probe leads to a different
jack.)

Then, disconnect ONE of the leads from your
controller from the track. Connect the controller
wire to one of your meter probes. Connect the
other meter probe to the track fee. This puts the
meter IN SERIES with the track bus. It therefore
measures the current draw of your loco. For the
test to be accurate, remove all locos and lighted
cars from the tracks, leaving only one of the 6 wheel
truck locos on the track. Slowly move your speed
control up and note the reading on your meter. It
should rise as the speed increases. Note the
reading when the loco triggers your 'breaker'.

Let us know what you find.

Another thought: How many DCC locos are operating
on your layout when the short occurs. Are there any
sound locos? They draw more current than non sound
locos.

Don


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