DCC Blue Box Consists Question

[cudaken]

 My BB F7 AB consists is doing just fine and been running the heck out of them. I have been thinking about picking up another A unit so I can have a ABA consists. If I do get another A unit, it will be facing backwards to the led A unit.

 Both the current A7's still have a hot chassis. Will this cause a short like it did when I was DC? I am using Kadee couplers. I am guessing there will be a short.

  Been having good luck with them so far and don't want to mess it up.

                     Ken

 

[wjstix]

There could be a problem with a short, although I have several Athearn F units and haven't had any trouble with them. If a problem shows up you could try using plastic couplers instead of metal ones, either working knuckle couplers or similar sized dummy ones like Accurail makes (which will couple with Kadees).

[jrbernier]

Ken,

  Even though the motor is now isolated, the frames will indeed cause a track short via the couplers.  The best way to avoid this is to:

• Use plastic couplers
• Use insulated coupler pockets with your metal couplers

  I drill out the 'post' on the frame and use a 2-56 screw to attach the entire Kadee coupler box/coupler - quite solid and 'insulated'  I have a permanent 'ABA' set of F's with dummy couplers - they set is always coupled...

Jim

[cudaken]

 Jim, I am guessing you mean the plastic screw the Kadee's come with?

 Look like I am going to be using the DCC ready F unit.

 Thanks for  the answer's.

                Ken

[rrinker]

 With the #5 style box, it doesn;t matter metal screw or plastic screw, the box itself is plastic and the coupler never touched the screw, even if using the center screw - there's that plastic post inside that the coupler pivots around.

 ANd with a plastic shank coupler, also it doesn't matter. It's plastic shank in the Athearn box, or grind off the AThearn pad and use any Kadee in their mounting box.

Plain #5 int he AThearn box, it WILL short if two units are placed back to back, just liek DC. One loco wil have the chassis hot to the left rail, the other to the right rail. And those kind of shorts are often hard to figure out - at rest they may not short, between the blackening ont he couplers and the loose coupling. But when one pulls and you get a more solid connection between the two - short.  It's very frustrating and if you don't remember that two of the locos do have the chassis connected to one of the rail pickups you might not think of that as a possible cause for the wierd running, random overload beeps, and jerky motion.

                  --Randy

 

[Truck]

According to Kadee's conversion chart your F7's would use the #37 couplers those come with the 233 style gear boxes. The coupler is insulated from the screw from the post molded into the gear box for the coupler to fit over. As Randy mentioned t can not short out.

Also I have a lot of blue box Athearn GP's & SD's With the same live frame set up. I can take any one of them with the Kadee coupler set up on them  and consist them forwards, backwards. Never had a coupler shorting problem with any of them.

                                                                        Truck.

[cudaken]

 OK, thanks for the additional information. I only had that kind of problem 1 time when I was DC. It was with PK2 BL2's. Soon as I turned the rear engine around, short was gone. But, now that I am thinking about it, the BL 2's do not use coupler pockets, just a clip that hold the coupler to part of the fame.

 A/B set up I am asking the question about, B unit uses the same type system as the BL 2's to hold on the coupler. A unit uses Kadee Coupler Boxes.

 Thanks for the help!

              Ken

[MisterBeasley]

If you always run this engine facing backwards with respect to the other units in the consist, you could look into reversing the trucks.  If they're like the older Athearns I've got, one side is isolated, and that side has a post and a wire coming off of it.  The rest of the truck, including the center frame, is powered by the other side.  That power flows through the truck and the center post to the frame.

If you turn the trucks around, you will change the polarity of the frame.  You have to do both trucks the same way, of course.

On my Athearn blue-boxes, though, I use the plastic coupler boxes.  That way, I know the couplers are electrically neutral and I don't have to think about which way the engine is facing.