Spectrum k4 4-6-2

[rwills7]

 :Rear trailing wheels derail backing up on a turnout.  Would it help to remove the spring and add weight ?

[Trainman203]

I'd check the switch first.  Where exactly on the switch is it derailing?

[rwills7]

derails as it enters the turnout to a dead end spur . nothing else derails.  switch checks out ok with guage

[DAVISinGP]

I've got a similar problem with my American 4-4-0 (52704).

It derails about 50% of the time when backing over a switch. Watching it very closely, it seems to be a problem with the lead wheels (which, when going backwards, are the trailing wheels) as they encounter the moving part of the switch rail - looks like the wheel flange often "ignores" the direction of the switch and tends to derail towards the center. The entire train will make it fine until the front wheels negotiate the area approaching the frog.

I've got to believe it's a "tolerance" issue between the loco's wheel flanges and the rails. I might try adding some additional weight as you suggest.

It's a bit frustrating as I've already sent this thing back twice for other problems.

[Trainman203]

It sounds like the point rail needs to be slightly filed a little thinner.

http://cs.trains.com/mrr/f/11/t/185197.aspx

[DAVISinGP]

It sounds like the point rail needs to be slightly filed a little thinner.

http://cs.trains.com/mrr/f/11/t/185197.aspx

Thanks for that suggestion and link. I'll look closer and maybe give that a try.

But note that all my other trains and trolleys run flawlessly.

[Trainman203]

I had that same problem with one renegade engine that just wouldn't keep its rear drivers on the rail backing through switch points.  Doctoring the points did it.

Sometimes individual engines are like hard to please people, each with its own very specific and high requirements.

[DAVISinGP]

Sometimes individual engines are like hard to please people, each with its own very specific and high requirements.

LOL - Now THAT I understand.

[ebtnut]

Always check the gauge of the wheelsets with an NMRA gauge.  If the gauge is slightly wide, this will cause derailments.  Also check the track gauge of the turnout, and giving a few swipes to the point rail with a small file is also a good thing.

[rich1998]

:Rear trailing wheels derail backing up on a turnout.  Would it help to remove the spring and add weight ?

None of my Bachmann tenders have a spring, only a pickup. Sounds like the points need attention or the wheels are a little too wide.

Rich

[jonathan]

Having over 30 Bachmann steamers (not the K4 unfortunately), my experience has been the drivers are always in gage. However, the pony/trailing trucks usually need a slight adjustment.

Fortunately the wheels on pony/trailing trucks can be twisted in or out using only finger pressure to make the adjustment (again, that's my experience).

If you do not have an NMRA gage/tool, you can remove the offending truck and hold the wheels up against the locomotive drivers.  That should give you a pretty good indication of whether the wheels need to be twisted closer or farther apart.

If all other equipment passes through the turnout points without problems, I would look to the truck, not the turnout.  Just sayin'. I could be completely wrong.

Regards,

Jonathan

[DAVISinGP]

I removed the front "truck" (the leading 4-wheel unit) and spent some time pushing it over the switch. The first thing I noticed was a significant bump at the hinge depicted by the arrow.

I filed it down just a bit, reattached the truck to the loco, and have been able to make 5 or 6 passes without a problem. As I mentioned above, my other (diesel) locos and my PCC trolley don't seem to have a problem negotiating these switches. My steam loco is certainly a bit more complex and, it seems, finicky. Not sure if the problem is resolved, but I think I'm on the right...track. (Yes, pun very much intended.  )  I'll keep watching.

[James in FL]

[ Not sure if the problem is resolved, but I think I'm on the right...track.]

I think so too...
Get your straight edge over everything.
You checked, all your wheelsets are in gauge... yes?
And your track too?

Good luck

[DAVISinGP]

[ Not sure if the problem is resolved, but I think I'm on the right...track.]

I think so too...
Get your straight edge over everything.
You checked, all your wheelsets are in gauge... yes?
And your track too?

Good luck

Thanks.

I don't have a gauge, but using Jonathan's suggestion above, I compared the wheels on the truck with the drivers and they seemed to be exactly the same width.

[Trainman203]

Those are really sharply curved switches, really too sharp for steam engines .  Graduate to no. 5 and no. 6 switches as soon as you can. 

Bachmann switches are notorious for that exact hump in the rail that you show, along with the frog being too high too.  Get used to leveling them both.   The frogs are a big enough job to need a Dremel motor tool with a grinder if you don't want to spend 3 weeks with a flat file. 

I have 10 or 12 Bachmann no.5 switches and while they are a perfect size between a 4 and a 6, every one of them suffered from poor workmanship at the point rail rivet as you show, at the frog, and losing electrical continuity at the rivet leaving the point rail dead.  They are good for train set use but I've had too many issues with them on a permanent layout.