My question is how close Funits should be coupled to be prototypical. I have two sets of P1K F3 A/B units and they seem to be coupled farther apart than I remember from my youth but I am relying on 40 year old memories so that is hardly a reliable source. Also the A units have rear doors and the B units have doors on both ends. Were F units connected with diaphrams like passenger cars to allow crew members to move from one unit to the other while the train was moving or were these doors just used when the locos were stationary.
nearly everything is/was coupled closer in real life than on a model railroad and yes F units mostly had diapraghms.
The early F units had drawbars and the roof over hang was tapered so the roof did not hit on curves.
3 feet between units except Baldwins which were two (I’m sure glad I never had to hook up any of those on a sleeting winter night). They started out w/ diaphragms but eventually somebody figured ouit it was cheaper to remove than repair them.
Whether or not the units were moving had/has nothing to do w/ going from unit to unit. Since the Milw SD 40s didn’t have folding steps and the handrails went all the way across w/ no break, going from unit to unit could be VERY INTERESTING. I suspect that, in this litigious era that might have changed
Here’s an F9 coupled between two B’s
Click to enlarge
The model manufacturers put longer than prototype shanked couplers to compensate for “toy train” radius curves of 16 to 18 inches. You can go to either draw bar or shorter shanked couplers if your curves are broad enough to allow navigation without the car bodies banging against one another.
Will
Several companies make HO diaphragms for F units. I used American Limited (with a homemade drawbar) on an Athearn F7 A-B set. On my Stewart FT A-B set I used their drawbar, it was coupled so closely that just using one black Walthers rubber diaphragm filled the gap perfectly.
BTW if the F-units were coupled together they would be farther apart than if they were connected by drawbars, so if you were running an FT A-B set connected by a drawbar, and the B unit was connected to the back of say an F3 (for an A-B-A set), the FT’s would be much closer together than the FTB and F3A would be.
3 feet from(MR) FOR F’s