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Picked up a new (it was on the shelf /display but sold as new) MTH 20-21453-1.  I am running on FasTrack - O36 curves. I have numerous other PS2 and PS3 engines, include some of the older (but still PS3) LV Premier F3s (i.e. trucks look similar) that run without issues a few times a week on the same layout.

I placed the new F3 near a curve and added it through the DCS remote - no issues.  Smoke unit kicked on, lights all worked, couplers fired, horn sounds OK.  Started to move through the a curve and it became slightly jerky then stopped for a second or so and continued on - probably 3 - 4 scale MPH.  Moved back and forth and it seemed to smooth out but still a little jerky at times.

Proceeded to 6’ or so straight - has an isolated outside rail running a relay for a signal bridge.  Relay is powered by separate 12V phased transformer.  Using two FasTrack 5” blocks to isolate the rail AND the center rail.  The entire layout is powered by the same fixed TIU output.  TIU is powered by a Lionel 180 POHO.  

The engine will get part way through the block, stop moving and quickly shutdown.  Cycling the power and trying to address the engine - remote shows engine not on track.  Pick the engine up and move it a few inches and turn power on - remote finds it and starts up - moves maybe a couple feet and same shutdown.   Tried this with the unpowered A coupled and it almost will get through the “block” but not quite - always stops and shuts down at the same spot, when the rear truck is just off of the block section.  Also the signal bridge indication driven by the relay toggles on and off when the engine is in the block.  When the engine stops and shuts down, the block signal shows green - i.e., the isolated rail is not grounded through the locomotive.  The signal shows red when the dummy is in the block (as expected).

Felt like it was a loose / bad ground.  Pulled the shell and checked the ground to both trucks.  Removed the wire from each truck and wire nut - ran a continuity test with meter from where the wire nut was to each wire - moved the wires around to ensure there was no break or bad connection.  Put the wire nut back on and tried w/o the shell and there was no change.

Hobby shop is over an hour drive each way.  Can certainly take it back - it is new and under warranty - but I have not dealt with this LHS very much.  Does anyone have any other suggestions to try or thoughts before I button the shell up, rebox it and head back to the hobby shop?



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Get an ohmmeter and measure the resistance between the front and rear pickups.  It should be close to zero.  Likewise, do the same for the wheel sets without traction tires.  It’s likely the wheel set to truck resistance, especially if the truck block has a plastic base.  The fit between the bronze bearing and truck block can be sloppy causing poor ground pickup.  We used some 0.005” brass shim material formed into a “U” shape to cradle the bearing into to truck block to make a tighter fit.  Also, if the ground screws have the black oxide coating on them, run a jewelers file under the head to remove the coating or use a nickel plated 3mm screw.  Premier 2/3 rail locos don’t have the best ground pickup.  It helps if both outside rails are grounded.

Thank you for the replies.  Things got busy at work this week - I finally had a chance to do some more testing / layout work this weekend and wanted to provide a quick update on findings.

@Krieglok - checked the wheels and cleaned them (loco was purchased new but may have seen some time on the in store layout - unit was reporting 30 scales miles and an hour run time) - got a little dirt off but nothing major.  Cleaned the track as well - no difference in behavior.  I did notice when it stalled in the outer rail isolated block moving the front truck side to side would change the signal aspect indicating contact between the outer rails (and common of the locomotive) was intermittent.

@Jon G - resistance between the front and rear pick ups (power / rollers) was between 1 - 2 ohms..  Resistance between the left and right wheel (same truck, wheel set w/o the tire) was 5 - 10 ohms.  Resistance between front and back truck wheels (again non-tire wheel) was 25-30 ohms.  Both power and ground screws on the truck are the nickel plated type.

I have three block sections w/isolated rail - one in a passing siding and two on the main loop.  Removed them all and replaced the Lionel jumpers on the block sections with 14 gauge soldered wires.  Engine now performs fine around the layout - all the way down to 3 scale mph.  I will switch to IR controllers for the signals.  Appreciate your suggestions / advice.

- Luther

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