diesel locos stalling on changing tracks?

[macaroni1st]

I have two ovals on my layout and changing from one to another  is facilitated by two sets of two Peco Insulfrog points back to back with isolating rail joiners between them . Each oval is powered separately from an analogue Gaugemaster series TS  controller which has  three separate outlets and control knobs. The polarity and direction on each oval is the same. Steam outline locos pass over from the outer to the inner oval no problem but diesels stall because of the long wheelbase and pickups on separate bogies? Is this because of the isolating joiners not being spaced etc.? Apologies for ignorance but every attempt to read up online or in a book gets too complicated for me to understand.

[StuAllen]

You don’t need the insulated rail joiners between the points, that’ll be causing the problem. Once the loco passes over them it’s no longer getting power from the track.

[Phil Bullock]

What diesels are involved? If you have a situation where one bogie is picking up one polarity from controller 1 and the second bogie the opposite polarity from controller 2 you have no circuit … hence the stall.

[StuAllen]

I’ve just been trying to find some examples to help explain it better. I’m assuming your layout is something like this (maybe without the extra siding), when the points are are set for each loop they are independent of each other and can have a train on each controlled by separate controllers. When the points are set to allow the loco to cross to the other loop either controller can power the loco but you cannot have both controller providing power at the same time. It must be one or the other. This only works if you’re using regular fishplates between the points. 
 

Hope that helps 

Edited January 6, 2022 by StuAllen

[BR60103]

Picture testing a loco upside down.  You have 2 batteries. Touch the + of one battery to the first bogie; touch the - of the other battery to the second bogie. (make sure it's the pickup wheels)  Nothing will happen because there is no complete circuit.

The same happens when one bogie is on controller A and the other is on controller B.

 

There are a bunch of techniques to overcome this, all in the "moderately advanced" wiring class. Common rail -- wire the inside rail of both loops together. Cab control -- isolate a stretch including one of the points and wire it through a switch to select one controller or the other. 

 

[macaroni1st]

Thank you everyone. I will revise things without the insulated fishplates being in the wrong place.

regards,

Tony.

[JSpencer]

The power source on both ovals should be the same (and just one source) as the loco goes from one oval to the next. The point work provides that power when they are switched to allow the crossing from one loop to the next.