switching 85' amfleet passenger cars

[winjie]

My 85' amfleet passenger cars keeps derailing with the standard switch machines. I am using Bachmann first railroad track pack at this time. If I add weights to the cars would this help.

Thank you gentlemen for your comments so far. I should have said that I am using Bachmann's standard turnouts. When the passenger cars go through the turnouts, the wheels on the cars that are close to the locomotive tilt and are the ones that causes the derailment. I am using bachmann's F40ph and HHP-8. Do I need larger turnouts. Thank you all.

[taz-of-boyds]

If weight would help just try piling some material on the car for a test. 

Depending on how it is derailing there could be problems with a pair of wheels set at the wrong distance on the axle (this is called the gauge of the wheels).  There are standards for the spacing between the flanges on the wheels on an axle.

Another problem could be the moving rails on the switch, these are the points.  If they do not fit smoothly against the fixed rails the flanges of the wheels can squeeze in there and cause problems.  The fix could be some careful filing to smooth it out.

If you still need help, please provide some more details.

Thanks,
Charles

[SteamGene]

What size turnout are you using?  Does it derail on the straight or the diverging route?
Merry Ninth Day of Christmas.
Gene