Lionel Metro North M7 keeps derailing

Add some fishing sinkers under the front. 

SIRT is certainly correct, weight is what keeps trains on the rails.  However, you might also check to see if anything is interfering with the ability of the lead truck to swivel freely - sometimes even wiring for ground or roller can bind up.  If the truck is held in the tangent track position, it'll derail on a curve and vice versa.

I have a M7 project in my queue, too, and will be interested to learn what the underlying problem and the ultimate fix is.

Good luck!

Thanks both.

I'll take a stab at it when I return home from the holidays.

I had the same issue and ended up getting a warranty repair from my local service station to lengthen the wires from the motor to the powered truck. They were too short and not allowing the truck to pivot.

I also took SIRT's advice and added weight to improve traction.

Jay in Ottawa

The wires need to be lengthened 

That is correct as well.
Its been so long since I bought the LIRR set, I forgot I also added to the wire length.
I discovered it because the wire insulation was getting cut by the wheel flange.
If it shorted out, that would have been a third issue.

Adding 2 lead fishing line sinkers under the front plastic shroud with silicone fixed the main derailing issue on my banked curves.
I had to add a metal rectangle plate - weight under the main section on the motor car also since it would slip on curves when using the 2 add ons.
I believe the full 6 car set was never tested by Lionel for trouble free operation.

Basically, it was a design oversite by Lionel.

On the wire lengthening.  The set never had any of these issues since I purchased it.  Ran flawlessly for 6 months until the past week. Could it be that eventually the shorter wires installed eventually caught up with the trucks and now I'm experiencing these difficulties?  I will try my hand at the longer wires as you all have mentioned when I get back home.

BTW SIRT, I love that photo image.  It is now part of my screensaver collection

You need to add the sinkers.

SIRT posted:

You need to add the sinkers.

Yes, those too.

Anybody know if this short wire  problem also exists in the LC set? I've had my eye on this set.

Finally got around to making the adjustments on the M7 Cab this evening, and it now runs like a charm!  Thank you SIRT!!!

I used two 1/4 oz sinkers along with some peel-n-stick weights (that can be custom cut) from a Cub Scout Pinewood Derby accessories.  I didn't bother to mess with the wires as both sets on my cab car barely had any play at all. Here are some pictures:

Glad I could help Kevin!