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Discussion Starter · #1 ·
Finished wiring my track using several power drops throughout, but still have some "slow spots". I've checked the voltages and there appears to no difference. Any thoughts?
Rick
 

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Sounds like maybe friction is the problem. Are the slow spots in curves or hills? Your rolling stock, do they have plastic wheel sets...Plastic gives more rolling resistance than metal wheels. How's the cleanliness of the track and loco wheels?
 
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Finished wiring my track using several power drops throughout, but still have some "slow spots". I've checked the voltages and there appears to no difference. Any thoughts?
Rick

El Tejon;

Could the slow spots be due to dirt on the rails in those spots. You can sort of check on the friction that Fire 21 mentions by pushing a string of cars, or even a locomotive (with track power off) through the slow areas. You may be able to feel a difference in the drag as you push.
Another possibility is out-of-gauge track at the slow spots, (though I would think that would cause derailments.)
If you don't already have one, order an NMRA gauge. (see photo) This is an essential tool for any model railroad. With it you can check the "gauge" ( the distance between the two rails) of both your track and each pair of wheels on your cars & locomotives. It can also check many critical areas on "turnouts" (track switches) It is a great help when you have to figure out why the train comes off the track. If this hasn't happened yet, it will.
An NMRA gauge only costs about $12, and is worth every penny. You can order one through your local train store, or from www.modeltrainstuff.com or www.trainworld.com Both are good honest online dealers.

Good Luck;

Traction Fan 🙂
 

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Reduced voltage or inadequate voltage for the purpose are the only two possibilities. If there is resistance through the rails, maybe a poor connection or some dirt that only lets a few volts through to the metal tires, then the locomotive's can motor will get reduced voltage from the decoder. In fact, the decoder should not behave well at all with reduced voltage because the voltage from the rails is meant to be sustained at about 14 volts in HO. Is this a DC setup?

The other is inadequate voltage for the purpose. If you set a speed step commensurate with about 30 mph for the locomotive, and it slows in spots, there is more 'work' to be done by the can motor than its supplied voltage will allow. It means too much trailing 'tonnage', or too much of a grade, or too much rolling resistance imparted from the narrowing rails at that point, including the effects of curvature. Some locomotives will slow on some places even when running light (no trailing cars) due to curvature or substantial grades. My own locomotives do that on my grades when running light. They simply slow more when trailing cars in the same spot. Note that combinations of tighter gauge, grades, and curvatures anywhere nearby, all add a cumulative effect on that poor can motor.
 

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I agree with Tractionfan. Friction could be the culprit.
Since you find that the track voltage is constant
at the 'slowing' points then friction should
be considered. There could be a narrowing
of the track gauge, squeezing the wheels against
the rails. If the 'slowing' occurs as the loco
is pulling a train the 'gauge' narrowing could
be anywhere...under the loco...or at some point
behind it when a certain car encounters the 'squeezing'.

Check that the gauge of your track is correct at the
points where the slowing occurs. It might be
helpful to also check the gauge of the loco and
car wheels.

You should be able to 'feel' the resistance if
you manually push the loco (or cars individually) thru
the track spots where 'slowing' occurs.

Don
 

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How did you fasten your track down? If you used track nails, you may have over driven one or more, bowing the tie and pinching the rails inward, creating an out of gauge location.
 
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Run the locomotives (without cars) through the "slow spots", one at a time.

Are they still slowing down?
  • If "yes", then check track gauge on the track AND the wheel on each loco (to be sure they are properly gauged).
  • If "no"...

...Then put together a short train and run it through the "slow spots".

Is it slowing down?
  • if "yes", could it be "resistance" from the train? Not only "at" the slow spot, but "before it", as well.
  • if "no"...

Put together a longer train, and run it.

Is it slowing down?
- if "yes", it could just be the weight of the train (harder to pull through curvature, etc.). Same as on "the big ones"...
 

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Until the OP returns and gives us some more information (perhaps after performing some basic troubleshooting), we're all just spitting into the wind.
 

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Discussion Starter · #16 ·
We need a few more details @El Tejon . Is it DC or DCC? What controller are you using? How big is your layout and what track is it? Are you using just one loco at at a time and what is the loco(s) and how old?
Sorry about the delay in responding. I didn't have the email notification turned on.
My layout is all vintage O27 from the 50's. My table is 9'x14'. I suspect several of the suggestions made are valid. I'll just need to start trying them out. Thanks for all the responses.
 

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Discussion Starter · #17 ·
Sounds like maybe friction is the problem. Are the slow spots in curves or hills? Your rolling stock, do they have plastic wheel sets...Plastic gives more rolling resistance than metal wheels. How's the cleanliness of the track and loco wheels?
Metal wheels on corners. Track and wheels appear to be clean.
 

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Discussion Starter · #18 ·
El Tejon;

Could the slow spots be due to dirt on the rails in those spots. You can sort of check on the friction that Fire 21 mentions by pushing a string of cars, or even a locomotive (with track power off) through the slow areas. You may be able to feel a difference in the drag as you push.
Another possibility is out-of-gauge track at the slow spots, (though I would think that would cause derailments.)
If you don't already have one, order an NMRA gauge. (see photo) This is an essential tool for any model railroad. With it you can check the "gauge" ( the distance between the two rails) of both your track and each pair of wheels on your cars & locomotives. It can also check many critical areas on "turnouts" (track switches) It is a great help when you have to figure out why the train comes off the track. If this hasn't happened yet, it will.
An NMRA gauge only costs about $12, and is worth every penny. You can order one through your local train store, or from www.modeltrainstuff.com or www.trainworld.com Both are good honest online dealers.

Good Luck;

Traction Fan 🙂
Thanks for the suggestions.
 

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Discussion Starter · #19 ·
Sorry about the delay in responding. I didn't have the email notification turned on.
My layout is all vintage O27 from the 50's. My table is 9'x14'. I suspect several of the suggestions made are valid. I'll just need to start trying them out. Thanks for all the responses.
 

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Metal wheels on corners. Track and wheels appear to be clean.
Unfortunately, the key words in thar sentence are "appear to be". Unless you have cleaned them recently, do it again.
 
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