You do realize the real ones had "play" between two units coupled with regular knuckle couplers? This is why the diaphrams were sprung loaded so they stayed touching as slack runs in and out between 2 units. Real F units, or any multipule lash up do not start or constantly run at the same speed, especially under light load, they will run the slack in and out in the couplers between them as they go down the track. Only under a steady pull with the slack stretched will they stretch the coupler slack between the units tight. Mike
Silly NT's, I have Asperger's Syndrome
All of my AB locomotives are connected by drawbar. I use 1/4” x 1/16” brass bar for my drawbars. I use 2mm screws to anchor them, strong enough to support the weight for carrying them. I’ve been doing it that way as long as I can remember without any problems. My norm is two powered E7s or Alco PAs, Athearn chassis’s with metal Cary bodies weighing over 2 pounds each. Never had any problems.I store them in my yard, a couple pairs of E7s and PAs. One pair with decoders and one pair DC, I run dual mode on my layout. Either DC or DCC, one or the other never simultaneous. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
Randy Stahl The real ones slam back and forth, whats the issue?
The real ones slam back and forth, whats the issue?
I agree, and as I pointed out before, if you are pulling enough train to need two or more powered units, they smooth right out.
Sheldon
It should be possible to beef up the mounting posts on knuckle couplers and reduce/eliminate much of the slop/slack action built into them. The remaining slop is in the knuckle itself.
At one time Accurail kits came with solid non-working knuckle couplers - before they created Accumate couplers - and it might be that their kits with old tooling still have those couplers on the sprue. There are other makes of dummy knuckle couplers as well - CalScale or PIA I think has some for example. The locomotives would have to be slightly lifted to couple and uncouple but that is what you did back in the day of the old Varney knuckle couplers and I have seen guys at operating sessions who do that with freight cars with working Kadees even now -- old habits die hard.
Dave Nelson
One thing I have done when I wanted the effect of a draw bar but to look like coupler is put a generous drop of superglue in the joined couplers, creating a drawbar. I'd use cheapo clones like McHenry. You can clip the uncoupling pins to indicate they're a solid unit. Dan
Replace the couplers with Sergents.
I've had a number of Stewart ATSF F units, and IMO they are the perfect "runner" for a layout. All units were powered, and I did use a drawbar - but only with the FTs. And, I only used the drawbar between the A and B units, putting KDs on the back of the Bs.
As pointed out, there are some downsides to drawbars, like having to handle both A and B at the same time. And I found that the drawbars supplied by Stewart were either too short or too long. So, I made my own, which really isn't that hard.
Another problem can be the screws holding the drawbars working loose, so a little ACC in the screw hole was often used.
I found the drawbars added some realism to the FTs, but if the locos are a problem and need to be handled a lot, they are just a pain.
ENJOY !
Mobilman44
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
Rigid scale couplers from old, old BB kits and Globe Gold F 7 kits. Older modelers surely will remember them:
Take Care!
Frank
BTW: Forgot to mention that the above coupler could be uncoupled, by just sliding one off the other........can't do that with a drawbar.
Well, I don't know what radius curves the OP is running, but the first thing I would do is close couple them so those diaphragms touch. That would buffer a lot of that slack action.
Pull a heavier train that really needs two powered units......
Do both units have sound? That will effect decoder performance and matched smoothness I suspect.
I run DC with no sound and I have Wathers Proto, Genesis and Intermountain F units that run together smoother than that in three and four unit sets.
My Walthers Proto C&O F7's do not have big gaps between the diaphragms like that?
PS - one more thought. Are these things brand new? Run them in a little and see how they are before doing anything to them.
I've draw barred a couple. I made the connection similar to the older locomotive / tender drawbars. It's mounted by a screw on one unit and the other end of the drawbar has a hole in it. The other unit has a pin that drops into the hole on the drawbar, so they can easily / quickly be moved individually.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Yea, I was going to suggest a draw bar, also. Stewart/Bowser had them for their EMD FTs. You might be able to purchase one from them. Or, if you're handy, you could make one out of styrene flat bar.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
You could use a draw bar, as some prototypes did. You'd have to handle both locos as one when you it on the track, and remove it.
Just make sure you have enough length for the tightest radius you have.
Mike.
My You Tube
Check out this very nice video. Starting at 1:01 you can see the A and B unit compressing and expanding against each other. Is there a way to do a more rigid coupling so that the A and B don't move relative to each other? I'm eyeballing my first set of F units, I want all powered As and Bs... but would like a rigid coupling.
https://youtu.be/IkTwFnM4reU?t=61