Kato Double crossover Stutters ONLY on one Route or Path

Mark Ricci Apr 24, 2021

  1. Mark Ricci

    Mark Ricci TrainBoard Member

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    Have a Kato double x-over in which both locomotives stall only when passing through one path or route of the crossover while passage thru the other route or path is flawless. Doesn't matter forward, backward, clockwise, counter clockwise...Running DCC but same behavior occurs on DC too.

    Feeds to all legs plus 6 other feeders on a very small 2' x 4' layout of 2 concentric ovals, the double x-over, 2 #4 RT and a #2 wye. 1 of the 2 loco's brand new Atlas SD35 other is a BL F3 bought 11/20. Wheels appear ok and seem aligned. Track cleaned every 2 weeks. Placed level along route with level center with x-over center. Bubble within line in both cases.

    Removed and flipped vertically, same issue. Tried brand new double crossover - same problem either orientation.

    Any idea's?
     
  2. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

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    Is this a stutter (stops/starts), stall (stops but layout still alive) or a short (power shuts off). I am betting the latter, since this happens with two different units, and doesn't matter the orientation. If it is, check all your polarities - you may have created a reversing loop.
     
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  3. mtntrainman

    mtntrainman TrainBoard Supporter

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    Yup...did this when I wired mine in too. One leg of the four coming off the dbl Xover was reversed polarity. A simple fix...(y)
     
  4. Mark Ricci

    Mark Ricci TrainBoard Member

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    Thank you for the reply.

    No short circuit seems to occur when either loco passes through the "bad" path or route regardless of using DCC or DC. Short circuit protection does not activate whether using Kato 24-018 DC Throttle or DCC base station. The only times it has activated (DCC or DC) is when accidently forgetting to throw a turnout and the loco shorts out against the point so the protection circuitry appears to be functioning.
     
  5. mtntrainman

    mtntrainman TrainBoard Supporter

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    Do the 'straight thru' legs of the dbl crossover function ok....both directions ?
     
  6. Mark Ricci

    Mark Ricci TrainBoard Member

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    Including track layout. Maybe helpful. Thursday swapped out #4 RT with straight track leaving only the d xover and 2 ovals. Still the same issue. All feeds "ohm'ed" out after soldering spade lugs when first installed.
     

    Attached Files:

  7. Mark Ricci

    Mark Ricci TrainBoard Member

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    Hi,

    Thank you for the reply.

    Yes, the straight thru is great!
     
  8. mtntrainman

    mtntrainman TrainBoard Supporter

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    One other thing I can think of...

    Loosen the small + screw that holds the points on the turnout...about 1/8 turn. Manually throw the switches to make sure they are working ok.

    [​IMG]

    Unitrack turnouts are power routing. They have to make good solid positive contact with the rails.
     
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  9. Mark Ricci

    Mark Ricci TrainBoard Member

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    All turnouts were changed to non - power routing but leaving powered frog (preferred for short locos) where applicable. No settings on double crossover. Going to do the 2 screws of the turnouts that are part of the bad path.
     
  10. Mark Ricci

    Mark Ricci TrainBoard Member

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    No change after adjusting screws of both turnouts that are part of the bad path.
     
  11. mtntrainman

    mtntrainman TrainBoard Supporter

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    HHhhhhmmmmmmmmmmmm. Let me think some more. I need more...:coffee::coffee::coffee::coffee::coffee:
     
  12. mtntrainman

    mtntrainman TrainBoard Supporter

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    You say it 'stutters' going thru. Will it go thru with a little finger nudging ??
     
  13. Mark Ricci

    Mark Ricci TrainBoard Member

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    Yes, or slight pressure to the top that's also why I don't believe a short is occurring either. I have a rather long log of everything that I've tried. Being new here, unsure if it is appropriate for lengthy posts so only key points included.
     
  14. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

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    Which part of the path is the stall on? Check to see if there is continuity on all 4 rails of the path to the rails on the exit.
     
  15. mtntrainman

    mtntrainman TrainBoard Supporter

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    Lenghty posts are the norm. It helps get to the root of most problems. (y)
     
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  16. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

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    Yes, please post details, as much as possible.
     
  17. Mark St Clair

    Mark St Clair TrainBoard Member

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    Have you tried moving the xover away from the curve so that the locos are on straight track immediately before or after the xover?
     
  18. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

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    Turning the x-over around doesn't really change anything on your layout, the same path is using the same two switches, so that doesn't really debug anything. However, substituting a different x-over and getting the same behavior says the issue isn't in the x-over.

    As I recommended above, double check that there is continuity on each rail to the adjoining rails, as it looks like your power drops are on the connecting track. My bet is you have a bad unijoiner in there (or maybe even an insulating unijoiner).
     
  19. Mark Ricci

    Mark Ricci TrainBoard Member

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    Part’s of the log copied from emails
    Since moving to DCC early last month as well as developing an interest running very slow prototypical speeds, it was discovered that the locomotive, an BLI F3, would either stutter or stall at moderate speeds (over ½ throttle 7-8) when going from the outer loop to the inner loop yet, moves wonderfully slow (throttle at 1) when going from the inner to outer loop (all counter-clockwise). Full throttle is 15 for reference. On Thursday, April 8th, went to Hobby Store and bought another Kato feeder wire
    Upon installing that feeder, (Feeder added 1 11”radius away from d xover leg-this was subsequently moved to the leg), there was an improvement and the F3 was able to go outer to inner at around 4-5 throttle stutter free. While better still believed more could be done. Then, Friday, decided to add another power distribution terminal barrier strip for left side feeders with 15 g trunk and reduced total Kato feeder cable length by about 7’. Also shortened feeders on right side but eliminated only another 10-12”. Wow what a difference! The F3 was able to get through between 2-2.5. Received a new Atlas SD35 on Saturday, 4/10/21 and slow speed performance through the crossover was outstanding too!
    Sunday morning both locomotives still performing well. Mid-day, disconnected base station to program the SD35’s new address. Reconnected and performance has been terrible ever since from outer loop to inner loop. Minimum non stuttering speeds outer to inner are F3 is 10 and SD35 is 3 yet very interestingly both locomotives can still go from inner to outer at 1! The F3, regardless on going forward or backward, and clockwise or counter clockwise, it is the front truck that is the stall point (center of double crossover) however when the SD35 stutters or stalls, it’s the back truck (forward - clockwise). One other interesting observation… On some occurrences going from outer to inner and when throttle is set in the 1-2 range, the SD35 almost appears to “hop” as it moves slightly past the center point but the F3 never does any “hopping”
    Ensured all tight connections at terminal block, cleaned crossover, insured rail points solidly contact rail, test ran jumper cables from clipping alligators from 2 closest power feeds and no change in outcome.
    4/14/21
    -The 3 closest attached and ballasted radii track going into the left side of the crossover (of both 11 and 9 radii were removed and a feeder placed between the upper right leg of the crossover and the #4 right turnout. Both upper and lower right side crossover legs now have power feed with no track segments in between.
    There was no observed increase in performance.
    -Flipped crossover so that turnout control wires exit the “bottom”.
    No impact
    -Removed double crossover back plates and carefully cleaned all copper contacts, re-assembled, and placed back in layout. (that was fun lol)
    No change
    4/15/21
    -Made 4 test feeder cables from uni-joiners, removed crossover from track, connected some spare track to each crossover leg (approx. 5-7”) with feeders on each end of the track (not crossover).
    No difference
    -Went to hobby store with the test rig and then test with a new crossover. No change but thought maybe insufficient length track length off of each leg.
    -Brought new d crossover home and inserted into layout, tested and then flipped crossover and tested again.
    No change just like when using my crossover however ironically, both locomotives actually seemed to move slightly better at any given throttle setting with the old crossover.
    Other observations. Regardless of the test, the slow speed performance has continued to be excellent when train goes from inner to outer look however (counter clockwise), and it is important to note that both locomotives seem to traverse the crossover stutter free at slightly lower throttle when sound is turned off BUT still not nearly like last Sat and Sun ( 2 day period). This observation coupled with the fact that from 4/9 when a feeder was added 1 11” radius away from lower left leg and a 2nd track power distribution barrier strip was installed, to last Sunday mid day when both these locomotives traveled through the nice slow speeds. The fact that the 2 day period is the ONLY time when all seemed great since setting up the track.
    Since both these locomotives were running excellent during the 2 day period following the addition the block and then suddenly, after just disconnecting base station for an hour or 2, had lunch and programmed SD35 and then reconnected suddenly reverting back to poor performance seems to point to unfortunately a bad feeder ( every feeder was “Ohm’ed Out” prior to installation), marginal or cold solder joint, bad barrier strip, eg. It’s hard to believe that both locomotives after great 2 day performance and after only about a period of an hour or so, either got dirty and/or truck out of alignment. I clean track 1x a week. Also, since the track wires to the base station are solid, not stranded, remember there was some “wire ricochet” when removed from base station on Sunday. Not severe enough to pull wires but loud enough to remember.
    All turnouts set for non-power routing and powered frog (where applicable and recommended for train layouts where mostly short loco’s are run). The #2 Wye has no powered frog. Have to go through at around 1.5 or 2 but knew that about #2s. There are set screws on the bottom plate of the turnouts that enable selection of routing and frog power. The turnout’s are configured based on the document; https://ntrak.org/resources/Documents/tNt/T-TRAK TipsNTechniques/TNT Unitrack Turnouts.pdf
    4/19/21
    -Removed the 1st barrier strip (right side-bottom); took 3 feeds off, removed soldered spade lugs (If present), re-stripped, tinned and soldered together to a 6” 18g solid and connected it to main track output (18g). Unfortunately, can’t move 2 feeders without splice but those 2 are the farthest from the double crossover and the new ones that were able to be moved are closer so those 2 would seem to have the least effect in maintaining power through the crossover.
    No change
     
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  20. Mark Ricci

    Mark Ricci TrainBoard Member

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    Part 2

    -Repeated entire process for 2nd barrier strip (left side-bottom), did 3 feeds

    -No Change

    The wiring underneath is now what we call a “Rats nest”

    -Repeated entire process for 2nd barrier strip (left side-bottom), did 3 feeds

    -No Change

    The wiring underneath is now what we call a “Rats nest”

    -Disconnected base station and connected Kato 24-018 DC power pack. Same performance issue. Couldn’t exactly quantify difference as there are few throttle markings but definitely the same performance variance between paths thru double crossover concluding that this negative performance issue exists under DC too. While another base station can be built, just received the parts, don’t see how that will change performance, from a Thevenin's perspective.

    did not want to totally discount a potential truck issue on SD35 but interestingly when nose is placed clockwise, and SD35 goes backward through the bad path, it is the rear truck, and not the front truck that “hops” over double crossover center which is why I didn’t think it’s a front truck issue. Most of yesterday’s tests were done with F3 but the few times the SD35 was run, same observations as all along. Think the hopping is more of SD35’s reaction to power than a mechanical or electrical truck issue.


    4/20/21

    Removed all spurs outside the concentric ovals and double crossover with exception to the right turnout-60Lmm with feeder and y turnout was all that was left as of last night. Only power feeders left are attached to track segments within the ovals.


    It occurred to me that all along always assumed that some connection was either intermittent or open and that was temporarily closed during the 2 day period. But what if it is the other way around, anotherwards some short or feedback was interrupted during the 2 day period instead allowing loco to pass thru both paths with ease. Cut 1 lead of that feeder between the RT and Y… and still no go.


    The SD35, the stall point, on 1 test the front truck is at center and on the other test the rear truck is at center. Primarily determined when the 35 passes thru the “bad” path either from the outer to inner--is the Front truck at center and inner to outer –is the back truck. I’m tending to discount loco issues because it’s really hard to believe that both locos after running flawlessly for 2 days; the F3, which was parked in a spur, and the SD 35 was only reprogrammed, and placed back on the track, that both SD35 trucks became faulty(electrically or mechanically) and the F3 got dirty or reverted back to malfunctioning as it was prior to the 2 day period.


    4/21/21

    Removed RT from d crossover leg and replaced with straight track leaving only the d crossover and ovals in the layout


    4/22/21

    With a level centered on the cross over, the bubble was within the lines regardless of whether the level was placed over the good route or path and the bad route or path.

    However still decided to try 1-3 shims underneath various combinations of legs….. inserted effectively business card stock thickness underneath the legs of the “Good Path” and magically performance on the Bad path approached the 2 day period. Isn’t that ironic? Both locomotives continued to run ok thru both double x over paths all day. (like 2 day performance of the prior week but still bad path needed about 2 throttle positions higher to get through-


    4/23/21

    -morning, eliminated rats’ nest for wiring on strip 1 (Cut off old tin, strip, re-tin and connect to block. Both paths continued to approx. equal 2 day period so far so good.

    afternoon, eliminated rats’ nest for wiring on strip 2. It kinda seemed like there was a reduction in performance in the bad path but not significant or like before the shims but was getting late.


    4/24/21

    am-both loco’s, regardless of shims and pressures placement, experience issue in the bad path. Not as severe as before Thurs morning but definitely noticeable.


    Thinking that the various stresses that the shims cause are compensating for some other nearby layout defect rather than being cure. Even considered possible AC-climate-humidity impact but the layout is located in climate-controlled space.
     
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