Train or cars derail going thru switches,have already replaced switches once ,doesnt matter which train i run

Usually because it is going too fast or the rails aren't properly latched..

https://www.google.com/search?q=Rocky+Mountain+train+set

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alignment tracks are the part of a rotating bridge that is where the tracks meet back together , this requires an alignment rail or train might derail , as this joint needs to remain movable so there is a gap there , typically it looks like a third rail spaced just inside the outer rail , this grabs and guides the wheel "toe" and centers the wheel onto outer rail , this feature requires frequent maintence as it does wear , as was evidenced few years ago by a bulk train derail in Louisiana as this was exactly what failed after crossing was hit by barge and train derailed

Is the track properly and carefully put together? Is one or more sections damaged take one of the cars and gently push it around watching in those places where the train derails. If it only happens at a track joint look at it more carefully.

Check your wheels to make certain the are still in gauge.

Sounds like the "variable resistor" that allows for a variable speed is either defective, or has become corroded on it's switch contacts. You might get lucky with some electrical contact cleaner spray and spraying it in or around the variable speed switch. Otherwise, I'd just invest in a new transformer.

Well you should probably check the radius of your curves. The Hogwarts Express has a minimum curve of O36 and on a tighter radius curve it will derail. I have found that the Hogwarts train runs better on fasttrack than standard O. You should also make sure the track is flat because if it isn't completely flat it derails. The train isn't designed well so it derails but if you run it slow you shouldn't have a lot of problems.

throutle safty switch just uplug it

sounds like it needs an ignition switch. the reason it dies after a few seconds after jumping the starter is bc the security system from gm thinks you're stealing the car so it kills the fire. the security system goes thru the key so if the switch is bad, it wont run no matter how you try to crank it

the switch on the dash needs to be replaced.

These furnaces goes thru 4--steps for complete run time.... step-1, the small draft inducer blower motor blows and prove thru the small air tube that sucks a switch close to tell the circuit board to go to step-2......the glow plug glows for 15 seconds and step 3 the gas valve opens and dump gas in the venturi tubes and lights off the glow plug and proves thru a flame sensor (pin with 1 electrical wire connection) on the last venturi tube which tells the circuit board to go to the last step 4--, to turn on the main blower fan after 90 seconds!. Where ever it stops at then thats where your problem is!