Intermountain F unit shell swapping?

[jagged ben]

So, I am on a somewhat long term mission (long term because of availability and cost), to acquire some late era Santa Fe F7s for my San Francisco Chief.

I know I could go with Kato but I'm kinda leaning towards IM because of appearance, and also because I managed to acquire an IM shell (only) for an F7B.  Hence questions...

IM F7s and F3s are the same mech, right?
What about FTs?

How about A vs. B units?  Can I put a B unit shell on an A-unit mech?  I gather the FT B-unit mech is particular to the b-unit, but what about the F7s and 3s?

I looked at  Spookshows writeups but they are not definitive on these questions?

[u18b]

The Fs use the same wheelbase.

You are correct.  The FT was different.

F2,3,7,9 all had same wheelbase.  As and Bs.

Of course you know that the FP7 was longer.

[jagged ben]

The Fs use the same wheelbase.

You are correct.  The FT was different.

F2,3,7,9 all had same wheelbase.  As and Bs.

Of course you know that the FP7 was longer.

Nah, I don't know nothin'.   This is a reach back out of my normal modeling era for me. 

So would an F3 or 7 A shell sit on a mech from a B unit?  Or are the IM A and B unit mechs different?

[Cajonpassfan]

Same mech. The B unit frame has the same contour as the A, resulting in a cavity where the cab would otherwise be. Good spot for a speaker in the B unit.
Otto K.

[jagged ben]

Same mech. The B unit frame has the same contour as the A, resulting in a cavity where the cab would otherwise be. Good spot for a speaker in the B unit.
Otto K.

Great!  Thanks.

[jagged ben]

Okay, gotta dig up this thread...

Putting an IM shell on a Kato mech...  Possible?

Specifically a B-unit  IM shell.   But interested if A-unit shell swapping is also possible.

[thomasjmdavis]

I can tell you that you cannot put an IM shell on a Kato mechanism without surgery that is beyond my capabilities.  The Kato frame was just enough too wide that the shell would not fit.  It was not so much an intended project

One of the thinks I have been hoping might come from a Shapeways designer that (it seems to me) would make a lot of sense would be a "dummy" chassis that could take Kato and IM shells -  fitting a plastic frame into either one would be a small matter of trimming or shimming, as opposed to grinding metal off the frame.  For purposes of prototypical accuracy and appearance, an ATSF Chief (Super or otherwise) needs 3-5 F units, but from a modeler's perspective, 2 is generally plenty of power.  I can understand why manufacturers don't want to produce dummies- extra assembly line, more tooling for the dummies, and in the end, you end up with a $100 powered unit and $75 dummy, and everyone gripes about how the dummy is too expensive.  But with shells going to $10-20, if someone could come up with a $15 frame and $10 pair of sideframes (or something like that), we would have the option to DIY.

[Nato]

                 Don't forget on Santa Fe Passenger F Units only the B Units had steam generators so for a moderate sized consist 10-12 cars A-B-B Units would be best,  the Kato Mini Pooper (Super) Chief set with a war bonnet A unit and three cars is just plain wrong to me as the A Unit has no steam generator. Nate Goodman (Nato). Salt Lake.Utah.

[thomasjmdavis]

Good point Nato.  That is one of the reasons that in later days, locals and other short trains were often pulled by an E unit rather than an F- it would be closer to prototype if Kato made those sets with an E8 and 3 cars.  Of course, such a train to be accurate would be something more like baggage-mail, coach, coach.  Maybe tack a 6-6-4 on the end.