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A Reversing Loop issue.

Discussion in 'DCC Control' started by Splitpin, Jul 6, 2018.

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  1. Jul 9, 2018 #21
    Sol

    Sol Full Member

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  2. Jul 9, 2018 #22
    Splitpin

    Splitpin Full Member

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    Thanks Sol that gauge looks easy. Two dings labeled wheels - I get it. :thumbup:

    Ran trains again today and it actually seemed less problematic - bedding in ? hmmm
     
  3. Jul 9, 2018 #23
    paul_l

    paul_l Staff Member Administrator

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    On Code 100 track the back to back should be 14.5mm.
    Hornby wheels are notoriously tight on back to back.
    Remove the wheel set from the coach (do it one axle at a time so that you can ensure the axle goes back in the correct way) grip the wheels and with a twist action ease out the wheels, insert the back to back gauge and twist the wheels in against the gauge. Re-fit and move to the next axle.

    Too narrow a back to back can cause the wheels to catch or ride up on the check rails, and on points that use that use the blades to switch the frog (V) polarity, if both blades are the same polarity then with too narrow a b to b the back of the wheel can short out on the blade.

    Too wide a b to b, then the wheels can lift out of the track on curves - especially tight curves made with flexi track as these don't gauge widen.

    Paul
     
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  4. Jul 9, 2018 #24
    RFS

    RFS Full Member

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    One other question - what DCC command station are you using? For an auto reverse module to work reliably it needs to detect the short before the command station does. A very sensitive command station can cut out before the auto reverser does. Also are you using a circuit breaker for the DCC bus? This too could be reacting faster than the LK200.
     
  5. Jul 9, 2018 #25
    Splitpin

    Splitpin Full Member

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    Hi Robert
    Command Station is a Lenz LZV100 v3.6, no circuit breakers. Track and accessories have separate busses but that's for the future, they are still combined into one at the command station currently. That wiring Bus and droppers is all DCC Concepts wire which looks pretty good quality to my eye.
     
  6. Jul 9, 2018 #26
    Splitpin

    Splitpin Full Member

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    Paul. That post contained so much knowledge and good advise that you've probably solved about half a dozen problems for me. My focus this minute is train automation. The biggest lesson I've learned that if I want one, two, three or more trains running automagically for half an hour the most important thing is reliability. Track laying as perfect as I can make it - that's the easy part. Then every wheel on every wagon/coach, every coupling for maybe 50+items across those trains, perfect or it'll fail. Much of my rolling stock is old, either because I collected it years ago or I've bought second hand since, even when I didn't have a layout to run it on. My #1 favorite coach rake are 1980's Triang/Hornby R122/R123. They and much of the rest have all had metal wheels and coupling conversion. So in the 2 weeks or so since the ribbon got cut on my new layout I've been running trains hard, going through much of my rolling stock. That means I have a growing pile of coaches and wagons that fail the ultimate reliability test and get replaced in the rake by another. What you've given me Paul is the cause to go with the symptom. Now I know why that wagon bucks every time it crosses the long crossing. I have one in particular I want to solve but I think I might start another thread for that one.
    But the quote of quotes for me was the "especially tight curves made with flexi track as these don't gauge widen". "Don't gauge widen" was a real AH HA moment for me.
     
  7. Jul 11, 2018 #27
    Splitpin

    Splitpin Full Member

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    Hiya Paul. I think I've found it. Even within the lack of accuracy I can achieve, I'm sure one pair of wheels is demonstratively tighter by at least .5mm than the other 3 pairs.
    Then I established the DCC Concepts BtB gauge is indeed 14.5mm of course. Jammed it in there, and so far it seems 'better'.
     
  8. Jul 11, 2018 #28
    Rob_B2805

    Rob_B2805 Intermittent mad modeller! [M4705] Full Member

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    I have recently installed a kit built reverse loop unit from MERG (£3.77 + p&P) and three train detectors (£1.85 each) plus a CDU for the point motor (£6.86), works just fine even with a Bachmann Blue Pullman (6 coaches, motor at each end). Well worth the cost of MERG membership.
     
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