BLI P70 - Correcting Coupling Distance How-To

[Lemosteam]

It may be a little too late for some, but if the rest of you can wait, I plan on designing 5 options for this car.

1: Individual direct swap replacement steps only, for those who still plan on following @cbroughton67 's 1016 attachment method

2, 3, & 4: Same step design with integrated snap in coupler mount, designed for specific aftermarket diaphragm distances, for those who do not want to cut material and add it to the car

5: Integrated step & snap in coupler mount, designed for the car's molded diaphragm distances

6: This is the potentially exciting part, I plan to design a link using the current kinematic coupler mount to have a ~1mm gap between cars when on straight track, which increases on curves to prevent corner contact but this would be for folks who will not be running ops on the passenger cars.

        - @nstars proposed the idea to me and confirms this would be similar to European designs
       - Since, as others have mentioned, the couplers would be basically hidden, I may be able to design a snap fit in the link's center for easy car separation and if I cannot get that to work the OEM screw would be
        used

Timing is TBD, but I need to get my hands on two cars first; @reinhardtjh (sorry I refused them the first time on FB) would you still be willing to mail two to me?  I promise to be really careful, and the only thing I might remove is the coupler, to get some accurate measurements.

@bbussey , for options 2, 3, & 4, can you describe the car mods you anticipate when installing the ALM diaphragms?  Would the other OEM diaphragms involve similar mods?

[bbussey]

So far, I’ve given the model just a cursory glance-over and put in on the track to observe the supernova lighting. But the addition of ALM diaphragms would require the removal of the existing diaphragms to start. How the current parts are keyed to the body, with tabs or pins or nothing, remains to be seen, but the face of the ends would need to be flat. I will investigate this weekend.

[randgust]

I've had surprisingly good luck with the 905's and put them on my Climax kits, the ore cars, etc. where a normal knuckle just looks enormous, and they are standard now for pilot couplers on just about everything.  And, on everything, of course, that I'm doing now in Nn3.

I do use magne-matic uncoupling, and I've found the 905's work if you simply rebend the trip pins a lot lower so that the tip is 'stretched' to reach.

Works great for my light logging trains, but the ATSF main line layout is a different animal with long, heavy trains and I already had to modify every MT coupler I had to reverse   draft angle to prevent pull-aparts, so I haven't even considered it there.

This is great team experimentation, but as many have observed, it's rather inexplicable that it ended up the way it did for a premium-priced product with extra engineering. 

Years ago I remember a 'hint' in one of the model magazines about putting a sheet of clear thin styrene over the ends of operating diaphragms so they wouldn't hook each other if they came off alignment.     I've also 'faked out' diaphragms with fan-folded pieces of thin black construction paper (another old, old MR hint) on the end of each car and was astounded how good that looked and they never hung or created a derailment issue.   Those actually could touch each other without causing problems.

[Simon D.]

This guy: https://www.mbmodelrailwayproducts.co.uk/n-gauge-products makes diaphrams (English translation, corridor connectors) from black card.

[reinhardtjh]

Timing is TBD, but I need to get my hands on two cars first; @reinhardtjh (sorry I refused them the first time on FB) would you still be willing to mail two to me?  I promise to be really careful, and the only thing I might remove is the coupler, to get some accurate measurements.

@Lemosteam PM sent.  But, yes.  I trust you. 

[Lemosteam]

This guy: https://www.mbmodelrailwayproducts.co.uk/n-gauge-products makes diaphrams (English translation, corridor connectors) from black card.

Interesting, but maybe not quite north american prototype?  NA style usually meet in the middle with a flange around the bellows.

[Lemosteam]

@Lemosteam PM sent.  But, yes.  I trust you. 

Thanks John!

[muktown128]

I just bought the P70 @spookshow had listed on ebay this morning.  I'm probably going to buy a 4 pack and several singles soon.

@Lemosteam - I'm definitely interested in what you're doing to develop a closer coupling / improved vestibule step after-market kit that would eliminate the need for a lot of cutting and trimming. 

Scott

[haasmarc]

I'm not totally sold on Z scale couplers...

Have others had better luck?

I have a home layout with pretty decent track work and I also do magnetic uncoupling using my own wound electro-magnetic ramps.  I have found the 905's to be more reliable doing remote uncoupling and I haven't had any issues with them touch coupling.  I have had an occasional uncoupling between locos but just occasionally.

When I got my BLI mikado, it had a broken tender coupler.  I replaced it with a 905.  I had to mount it without the lid (not for the faint of heart) to get it as high as I could without machining the tender floor.  It is still a little low but has been working well (don't get me started on needing a z scale underslung coupler).  That engine switches cars right out of the box nicely.

Standard n scale couplers usually need work to make them remote uncouple reliably.

[Maletrain]

Marc,

Would you share your design for your "own wound electro-magnetic ramps"? 

I am considering using 2 for a scale house situation where, in my era/locale, each car must be uncoupled to be weighed.

[dougnelson]

It may be a little too late for some, but if the rest of you can wait, I plan on designing 5 options for this car.

1: Individual direct swap replacement steps only, for those who still plan on following @cbroughton67 's 1016 attachment method

2, 3, & 4: Same step design with integrated snap in coupler mount, designed for specific aftermarket diaphragm distances, for those who do not want to cut material and add it to the car

5: Integrated step & snap in coupler mount, designed for the car's molded diaphragm distances

6: This is the potentially exciting part, I plan to design a link using the current kinematic coupler mount to have a ~1mm gap between cars when on straight track, which increases on curves to prevent corner contact but this would be for folks who will not be running ops on the passenger cars.

        - @nstars proposed the idea to me and confirms this would be similar to European designs
       - Since, as others have mentioned, the couplers would be basically hidden, I may be able to design a snap fit in the link's center for easy car separation and if I cannot get that to work the OEM screw would be
        used

Timing is TBD, but I need to get my hands on two cars first; @reinhardtjh (sorry I refused them the first time on FB) would you still be willing to mail two to me?  I promise to be really careful, and the only thing I might remove is the coupler, to get some accurate measurements.

@bbussey , for options 2, 3, & 4, can you describe the car mods you anticipate when installing the ALM diaphragms?  Would the other OEM diaphragms involve similar mods?

Hi John:
I would be definitely interested in a solution with the steps and coupler pad.  Did you look at the exploded diagram for the care on the BLI website? 
http://www.broadway-limited2.com/support/N%20Scale%20P70%20Coach%20Expl%20View%20-%20Type%20B.pdf

The kinematic coupler mount option is also an interesting idea.

Regarding the American Limited diaphragms, typically I just remove the stock diaphragm and use Goo to glue the new diaphragms on.  I have not yet tried with the BLI cars.  With the Model Power/Lima P70s I believe that I shave the inside of the molded car diaphragm to achieve a flush fit for the American Limited diaphragm.  For me, they work well.  I have hidden curves down to 14"R.

I look forward to hearing more.

Chris Broughton: Is there a reason that you used MTL 1016s instead of 1015s?  It looks like your cars could stand to be even a little closer.  Thanks for posting this.

[haasmarc]

Marc,

Would you share your design for your "own wound electro-magnetic ramps"? 

I am considering using 2 for a scale house situation where, in my era/locale, each car must be uncoupled to be weighed.

Maletrain,

It isn't my design.  I got it out of one of the magazines probably 15 years ago.  Basically, you take steel shelf channel and cut it into about 2" lengths.  Then you glue them back to back and file all the edges round and smooth .  Then I take thin styrene and wrap it around the core for added protection then wrap the whole thing in electrical tape.  Then you wind magnet wire around the core around 350 times (doing this from memory but I think that is the number of turns).  Check for a short between the two ends.  Mount directly under track, centered,  with the top of one of the "U"s  as close to the track as you can.   Hook it up to a 25vdc source through a push button.

To make winding easier, my dad took some kind of right angled contraption out of the junk box and added a mechanical counter.  You chuck it into a drill press and attach the core with double sided tape.  I put a foot switch on the drill press to control rotation because both hands are occupied guiding the magnet wire.

One other thing.  Since this is basically a direct short, you can't hold the button down for long.  The ramp will warm up eventually.

[Maletrain]

Maletrain,

It isn't my design.  I got it out of one of the magazines probably 15 years ago.  Basically, you take steel shelf channel and cut it into about 2" lengths.  Then you glue them back to back and file all the edges round and smooth .  Then I take thin styrene and wrap it around the core for added protection then wrap the whole thing in electrical tape.  Then you wind magnet wire around the core around 350 times (doing this from memory but I think that is the number of turns).  Check for a short between the two ends.  Mount directly under track, centered,  with the top of one of the "U"s  as close to the track as you can.   Hook it up to a 25vdc source through a push button.

To make winding easier, my dad took some kind of right angled contraption out of the junk box and added a mechanical counter.  You chuck it into a drill press and attach the core with double sided tape.  I put a foot switch on the drill press to control rotation because both hands are occupied guiding the magnet wire.

One other thing.  Since this is basically a direct short, you can't hold the button down for long.  The ramp will warm up eventually.

Thanks for the info.  What I am getting from it is that there needs to be 350 turns and 25 volts DC for the magnet strength.

Not sure what you mean by "shelf channel".  I am envisioning the 5/8" wide steel U-channels that screw to a wall vertically and have vertical slots for brackets that serve as shelf supports.  Assuming you mean to put two U sections together with the closed ends touching, and wrap the wire lengthwise inside the channels.

If I have all that right, then the only question remaining is what gauge wire did you use for the 350 wraps?

[CRL]

Oh, oh... I know, Mr Kotter... magnet wire! 

[peteski]

The 350 turns and 25V is nebulous info without knowing the wire gauge.

Also, by changing the number of turns and the wire gauge, one can make an electromagnet (which is what these things are) that will operate from a typical 12-16V DC throttle or power supply.  25V is not something often used on a typical N or H0 scale layout. 12V is.

The statement that the electromagnet is a "short" is also not entirely accurate.  25turns of copper wire will have some inherent resistance (not a "dead" short). The resistance is again dependent of the wire gauge.  It will likely be several ohms.  But yes, with low resistance there will be a good amount of current passing through the coil of wire, heating it up.  Similar to how twin-coil switch machines work - you only momentarily activate them, or they will burn out from overheating.  But an uncoupler needs to have high enough of a resistance to withstand several seconds of being powered, to make it usable.

Instead of making one, why not buy one.  Here is one on eBay with only a $3 bid.
https://www.ebay.com/itm/N-SCALE-KADEE-1309-THRU-THE-TRACK-DELAYED-ACTION-MAGNE-ELECTRIC-UNCOUPLER/333322566408

Here are some instructions on how to make one from the H0n3 version:
http://www.aglasshalffull.org/N-Scale-railroad-info-and-pictures/article-uncouplers.html

https://www.modelrailroadacademy.com/video/build-electromagnetic-uncoupler-train-011164/

Another thing you might want to consider is a hinged under-table permanent magnet uncoupler which is located under the track when used, then swings down when not being used.