N Scale 4-8-4 Front Trucks keep derailing

[Clovis-73]

I have a Bachmann 4-8-4 running on Kato Unitrack R381-30 degrees curved track and the front Pilot Truck wheels keep derailing. I have not modified the truck, in other words, I have not changed out the wheels or anything else. Any suggestions?

Thanks,

Jim

[seadowns]

Hi!
It may helpful to check with the space between the wheels. Very often ist the derailing to be cured by extending or narrowing the wheelspace a tad.

Regards
Mathi

[James in FL]

I'd check the wheel gauge first also, chances are its tight.
If yours is so equipped (newest version), check the spring tension between the top of the truck and bottom of the frame too.

[skipgear]

It would depend if it is the J class Northern or the Santa Fe Northern. The J has a spring, the Santa Fe does not. I have added a small leaf spring to a Santa Fe Northern that was particularly peski. Check wheel gauge, check for interference and finally watch the loco up close and slow till it derails the truck.

Also, make sure to check your track, Kato track can have a bad joint just like other brands. If it derails in one spot constantly, check the track.

[Desertdweller]

Tony,

I have an ATSF Northern that has that problem.  It looks great and is actually a smooth runner, but gets no use because the front truck keeps derailing.

I put a spacer block atop the front truck to limit its vertical travel, but that didn't work.

I've got a lot of coil springs from converting my older equipment from Rapido couplers to MT ones.  Maybe I can use one of those.  If not, could you tell us how you made and installed your leaf spring?

Les

[skipgear]

My spring is just a piece of Phosphorbronze (Brass works also) that is fashioned to look like half of a half axle pickup wiper. The hole must be small enough that the stepped screw will tighten down on it. The finger presses down on the top of the pilot truck. It takes some fiddling to get the right tension so that it holds the truck to the rails without lifting the front of the loco.

[James in FL]

Not sure which version of the Santa Fe you guys have but mine came equipped with a spring. It appears to be phosphor bronze.
It was purchased new in '06 and came in the plastic jewel case.
According to spook, it is the newest split frame revision.
I will post a pic late tonight after work.

[James in FL]

[wps]

i have a bachmann 4-8-2 light mountain which had the same problem.  I used a very small split shot sinker, hammered out very thin and then glued to the top of the pilot truck staying away from the wheels and making sure the pilot will turn.  This added weight did the trick and  have had no more derailments.  Good Luck

[Desertdweller]

James,

My Santa Fe 4-8-4 has the little stamped spring yours has.  I thought it was some sort of electrical contact between the front truck and frame.  Apparently, it was too short to apply pressure to the front truck in the center, where it needed to.

My spacer block idea (actually, I glued them to the frame above the lead truck) did nothing to solve the problem.

I took Tony's idea and made a longer flat spring out of thin brass.  I used a strip cut from the framing from a photoetch fret.  It is as wide as the original little stamped spring, and about an inch long.

I put a hole through it the same size and distance from the end as the hole in the stock spring.  I held the spring in a needle-nosed pliers and bent it down at about a 10 degree angle, with the bend slightly forward of the hole.

This new spring was installed in place of the stock spring.  I had already gauged the lead truck wheels correctly on my previous attempt.

By golly, it worked!

Thanks, Tony and James!

Les

[James in FL]

By golly, it worked!

Good to hear.

used a strip cut from the framing from a photoetch fret.

Ya didn't use the wife's good scissors did ya?

[Desertdweller]

No James.

I did learn that much in 38 years of marriage.

Les