4-6-2 not clearing X-over

Without seeing the engine I am only offering possible solutions. If the AM crossing has an insulated gap greater than the distance between the pickup tender wheels than the locomotive will stall at the crossing. Make sure the wheels are clean and that the wipers are actually touching the axles. Some trucks are bent so that only one axle is actually touching the rail, therefore only one wheel is actually transmitting power to the loco.  Loco wobble can be caused by worn pulmor tires. Loose driver insulation and metal tires or drive wheels, wrong gauge, too close together.  I hope this helps.

I agree with what Major says about the trucks on the tender especially the sheet metal trucks. Sometimes they will get bent or sprung just from handling or traveling. You can check these out by lightly an slowly setting the tender down on a piece of straight track and watch as the wheels come in contact with the track. I had a couple of tenders with this condition, you will see one wheel contact first and then one on that truck diagonally opposite make contact. This can easily be corrected by bending the truck back in shape by hand. You will much improve the performance by doing this.

The wobble may be caused also by wear in the axle hole in the chassis, try locking the reversing unit in forward or reverse and put the engine in a cradle upside down and apply power with jumpers to see if the axle with the worm gear is causing the wobble, the worm may be bottoming in the gear.

Hoping this helps also,

Ray