Re: Lionel NKP 765 Derailing Question

Bob RumerOGR Forum Member DIGITAL SUBSCRIBER

I finally have my NKP 765 running after getting front truck fixed. This is truly an awesome locomotive, hearing Rich's voice makes it extra special.

The whistle & whistle smoke is awesome.

I can't figure out a back truck derailing problem on one particular curve that will derail every time. I operate two mains, the outside main has softer curves so I tend to run the larger locomotives on the outside main. I fully understand the suggested minimal curve for the locomotive, however I operate Lionel Northern, 4-8-4 and Lionel Reading 2100 4-8-4 on this line without any derailment.

I have Fast Track 072 - 060 - 048 - 036 curves at different locations along the main. The track that causes the derailment is a 048 curve.

The leading wheel of the back truck on inside rail lifts off the track when inching it or regular speeds. None of my other locomotives have this problem.

I watched very closely to see if tender and engine were touching on the curve, they were not. Anyone have an idea why the wheel is lifting off?

My inside main line has tighter curves, mostly 048 & 036, some 060. The 765 runs fine without any derailment.

Bob

12/20/148:38 PM

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cbojanowerOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBERMEMORIAL SUPPORTER

The engine is rated minimum O-54

12/20/148:40 PM

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Captain JohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBERMEMORIAL SUPPORTER

Bob, if I'm not mistaken I think the manual on the 765 says 054 radius minimum.

12/20/148:42 PM

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suzukovichOGR Forum Member

I know this may sound funny, but I had the same issue with a Weaver engine only it was a 072 half curve section. It turned out that the track had warped with the outside rail lower than the inside rail as it entered that section.

12/20/148:52 PM

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Forrest JeromeOGR Forum Member

I had this issue with the first legacy 765. Turns out a little grease on the rear truck around the slot at the rear of the truck that moves from side to side on the post did the trick. It was binding and caused the wheel to climb the rail.

12/20/149:03 PM

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Bob RumerOGR Forum Member DIGITAL SUBSCRIBER

Thanks Forrest, I will apply some grease as you instruct.

Thanks Suzukovich, I will check for a warped rail.

Bob

12/20/149:38 PM

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rockstars1989OGR Forum Member

Minimum curve ratings are certainly not an exact science.It may be rated for O-54 curves just not YOUR O-54 curves.Another thing and I know this sounds nuts.But some locomotives have to be broken in on your layout.My new Allegheny was de railing on a certain O-72 curve on my layout.I did everything I could…I was going nuts.After a while running it the problem went away.Good luck.Nick PS: you have built an amazing layout! Try removing the track screws from your problem curve.The ever so slight amount of flex may solve your problem also.

12/21/148:46 AM

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Bob RumerOGR Forum Member DIGITAL SUBSCRIBER

Problem solved two ways.

First, thanks again Forrest, lube the rear truck fixed it!! Awesome.

Problem # 2 solved. Thank you Nick, when I turned the 765 to run opposite direction the front truck would derail in a different location. This is on back part of my layout on a sharp curve (036 -ouch) reading your comment I removed screws and applied a shim banking outside rail. Works perfect!!

I ran the 765 for more then a half hour with no problems.