MTH 20-21453-1 CNJ F3 Stalling and Shutting Down

Just to get things rolling, it sounds like a track issue. That or possibly dirty wheels on the locomotive…

Tom

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

Cool. I guess some added complexity to the power delivery system (track) has an effect on the sensitive control systems on engines.

Glad to hear you are up and running again!

Tom

I'm guessing this is a 3-rail/2-rail switchable engine, those are notorious for wanting both outside rails to be common.

I considered a problem with one of the outside rails not being common. I have encountered that with my test track, actually…

Tom

I've rewired a bunch of these for 3-rail only for customers, usually when the ten cent switch craps out and they end up paying for a repair.

We connected all insulated outside rails to common ground due to this as a lot of guest MTH F units of all types were doing the same thing. Solved the same issue at switches with the non-derailing feature.

Unless you're doing insulated rail signaling, I see no reason not to tie both outside rails together.