6 axle engine derailment through Atlas #6 turnout on mainline

[Anonymous]

I have two 6 axle Bachman spectrum engines (SD70MACS). Both derail almost every time they enter the frog on mainline at the opposite end of where the points are located. As near as I can tell the wheels drop into the hole of the frog then try to climb out the wrong way. I have searched all the forums I know of and can't seem to find anyone else with this problem.

I have gauged the turnout with the NMRA guage and did find that the guardrail's opening was too wide, which I corrected with a styrene shim. Had no effect on this problem. Both of the engines wheelsets are in guage. I have absolutely no problem with 9 other engines of various makes that have 4 axle wheelsets.

The track is flat and secure although there is a curved incline bottom 12" from the beginning of the frog. There is also a rerailer in that span.

HALP!!!

Regards,
Marty

[Anonymous]

What happens in reverse?
What happens when you pick the engine up and turn it around, forward, reverse?

[retsignalmtr]

theres a possibility that the trucks are not swiveling enough when going through the turnout causing the flange to pick the point of the frog. i've had that with other brands of locos when the swivel motion of the trucks binds up and the truck tries to stay parallel to the loco frame.

[Jacktal]

One simple method I use for checking possible track problems...I use a 4 wheel truck that I pu***hough the turnout at different speeds.If it does occasionally derail,I simply roll it slowly while pressing it lightly down with a finger.This allows me to feel any dip or bulge in the turnout,and where the defect is.For what it's worthed........

[Anonymous]

Bachmann SD-70MAC"s???, I didn"t know they made em.

Mac

[Anonymous]

You may also try shimming the frog depth if your other equipment does not have deeper flanges than these locomotives. This would be easy to try using a little styrene to see if it makes a difference. Let us know your progress.

[SP4449]

Of the three axles in the truck of the locomotive, does the first, second, or third axle derail the loco? Is it the lead or trailing truck? Check for too much vertical play in the second axle. If it is dropping down into the frog area, it could be jamming the truck and causing it to derail. The shim in the bottom of the frog is a good idea and also finding a way to limit the vertical motion. The gear that drives the wheel set may be locking up when the alignment changes as the wheel drops into the frog.

[Eriediamond]

Since both engines have the same problem, I would think the problem is the turn out. Is there other turn outs on the layout and do these engines negotiate them ok??? Which direction into the turnout do they derail? If it's hapeening when the engine enters the switch from the end opposite the points, (from lets say, a passing siding) into a #6 turnout and the engines are fairly long the trucks are not fully "set" yet which means that on a left hand turnout the lead truck is being forced to try to turn left by the rear truck swinging the rear of the loco to the right. Since the front truck is basicly trying to negotiate a right hand turn the front truck is in a bind as it crosses the frog. Am I makeing any sense here?? Since a #6 turnout is basicly still a "tight" turnout for long six axle locos this could be the problem. Full size railroads use a little extra curve out of there switches then swing back in to alignment with the parallel track so the trucks are set when they enter the switch from the "tail" end of a small number turnout. Best of luck to you, Ken

[Anonymous]

When did Bachmann make SD-70MAC"S, I think you are referring to Athearn or Kato locomotives.