Does the click occur even at very low (creeping) speeds? If so, repeating the test over and over while watching each of the trucks, one at a time, may help reveal what or where the problem is. Even if the audible click does not occur at low speed, sometimes a sudden movement can be observed (that likely rises to audible at higher speeds). Also watch the movable point rails during this exercise, to see if they are rocking (e.g. side to side, etc.) as trucks roll on and off them.
Thank you @BigJake for the info. Click is heard anywhere between slow and mid speed and, when first axle wheels of the front truck impact the rail continuation crossing mid point of DxOver. Video below... If stop train.. Close DxOver, then throw it, restart loco... It may go around a few times before fist click so unlikely caused by DxOver?? And click only heard approx 1/5x without any change in throttle or path.. Perhaps the most interesting aspect of the problem. just making laps around ovals alternatively switching between them via DxOver... On another video with loco sound, click occurs at same point and then sound stutter a second or so after. The sound stutter only happens after click. Unfortunately, everything except the SD35, GP7 and brick power supply is packed up. :-( Haven't decided to remove some or all of the under layout electronics so may have a little more time to explore.
The first video looks like the one of the lead trucks' wheel flange is catching and trying to ride up on the insulated rail joint in the middle of the double-crossover. That would cause an audible click when it plops back down on the wheel's tread. You might run your finger along the sides of those center, insulated gaps in the rails, and see if you can feel something the flange is catching on. You might be able to fill any mismatches in with epoxy, and file/sand it down smooth after the epoxy is cured. That loco sure likes to try to climb any imperfection it finds...f The sound stutter is probably the decoder losing power and resetting, then restarting, from the truck loosing contact with the rail. That indicates the rear truck may not have good electrical pickup. Does the loco do this when it backs through the crossover on the same path? The motor has enough momentum to coast through the interruption, even at low locomotive speed, so any loss of speed is less discernable than the sound decoder restarting.
I agree. To my eyes and ears, it's a wheel gauge problem. I can't recall if @Mark Ricci checked all six axles using an NMRA tool.
It's also possible the plastic areas of the double crossover are miss-fitted to the rails (or vice versa) somehow, causing exposed corners/edges that catch the wheels/flanges as the cross. Both of my double crossovers are flawless, but any mass-produced item can occasionally be flawed. Sometimes, simply running ones fingers along the rails (especially the top, inside corner of the rail) can detect such flaws, and a small file or sharp knife can remedy the situation.
Thank you @BigJake @Hardcoaler ... Additional info... a-Click not heard when moving loco backwards thru same inner - outer path after about 10 trials. b-Reviewed a number of videos from last May (prior to 1st service) thru same path and none revealed click. Swapping out with new double crossover last year had no observable difference with either path. Focus was on the much more problematic outer to inner path but think would have heard click during the many compare and contrast tests conducted last year. c-Finger test along rail junctions at DxOver center do not feel abnormal in comparison to other track segment junctions. d-Have not checked gauge since last service call. Will check gauge and report back. Limited experience but found this earlier today as guide to help.. https://www.nmra.org/sites/default/...p-2_2019.07.07_typo_correctiontrack_gages.pdf e-Unsure if of any significance and maybe splitting hairs but... Prior to moving layout on coffee table, the F3 never made thru same inner-outer at SS 1/127 but ok at 2/127. On coffee table, F3 generally no issue at SS 1/127. Checked layout with level and nothing outside lines compared to layout on 46" legs. No difference in GP7 performance - legs vs coffee table. No history running the "improved" SD35 when layout was on 46" legs. Wondering if this problem and the clockwise forward inner - outer major derailment. Have not performed much testing because derailment in DxOver always results in shorting the rails. Curious... What are the ++(s) and --(s) of different wheel flange sizes, at a given code rail, in terms of track performance eg. derailments, smoothness thru turnouts?
Maybe if you were to bring the layout and SD-35 to the southern hemisphere, the unit's troubles would be evident only when moving forward in a counterclockwise direction? My best guess is that your CNJ SD-35 is simply homesick and your move to NJ will restore its happiness.
