Postwar F3 kicking into neutral

Well I have postwar SF F3's and that happens as well. I just choose not to use switches on one loop and run the F's there. It might be that some part of the switch hits the E unit lever on the bottom of the engine and kicks it into neutral. Just my theory for my own engine. 

Yep. I've had other engines have the E unit lever hit before too. First thing I thought here also. Not the case though. Lever is fine. Sounds impossible, but it's happening. Burfle might know.

Thanks for the reply

Can you tell if the solenoid is activating, or if the drum is turning on its own?

Does it do it in facing in both directions? If it is locked in "N" the lever has to move to energize the coil again.

Exactly which switches do you have?

He says he has these:

You know, I can't now remember if it goes into the "buzz" mode. Like in neutral or not. I'll pay better attention next time. I think it just quietly stops. Lights still on. It's made many round today with no issues. Yesterday it did it many times.

It is not locked in neutral when it quits. It's locked in forward. And the lever remains there. 

Yes, those are the switches.

I'm no guru like some of you gents, that's why I'm asking, but I'm also not new to these things. We've all had locos kick into neutral on switches before for various reasons, roller spacing etc.  The easy fix is to lock the thing in forward and it keeps on rolling. That's why this is odd. It's no doubt LOCKED forward and the lever is NOT getting hit. 

No Bailey's in my coffee either! 

I had a F3 that did that. The roller would lift high enough to hit the truck. I put some tape or foam where the roller hit and it solved the problem.

"Locked" is not really a state that means anything when you are talking electro-mechanical E-units. The solenoid is simply turned off by means of a SPST switch(e-unit lever).

If the drum advances or retards(and it can) without the solenoid being activated, this is due to a loose fitting of the drum in the housing and vibration while traversing the tracks.

Alternatively, if the solenoid is activating while the lever appears to be in the "off" or "locked" position, it's because something is causing the circuit to the solenoid to complete, albeit briefly. This could be a loose rivet allowing the lever to swing by vibration, or the fiber terminal  panel swiveling on same rivet, or an errant wire/lead that contacts the lever making the e-unit advance.

I'm going to bet on the vibrations from operating. Makes sense. Just sounds correct for the way it's doing it. This gives me some direction to check out.

Thanks for all the info. I appreciate it very much.

It could be that the e unit fingers are worn so thin that the ends have bent back releasing most of the pressure on the drum. In any case, you might be able to jam the e unit drum in place with a tooth pick until somebody can look at the e unit. 

David Johnston posted:

It could be that the e unit fingers are worn so thin that the ends have bent back releasing most of the pressure on the drum. In any case, you might be able to jam the e unit drum in place with a tooth pick until somebody can look at the e unit. 

Good possibility. I'll check it out. I'm not a certified tech but can work on a good amount of components on the oldies.  Now this newer stuff I see these guys post pics of while working on looks really spooky to me.

My money is on the drum and/ or finger positioning. But all of those are more likely than...

 In theory an errant magnet field could randomly transfer to the prawl or coil. A sheild placed around it would be an interesting and easy thing to do for a test.

Is it a vertical pull? Horizontal pull it would increase the chances.