A potentially use discussion thread would be one dealing with known practical body swaps. A current post about the Intermountain “Smart Dummy” has led me to wonder what non-Intermountain bodies might fit its chassis without major surgery. Question, of course, can/should extend to all manufacturers.
What’s your experience?
I’ve done a couple: Lionel GP30 onto Athearn GP frame/running gear and a Rivarossi E8 onto a Model Power E frame/running gear. In the old days when good versions of each were not available [:D]
Sorry, can’t help with the IM frame.
It’s interesting as to what can work. Oftentimes, one manufacturer’s shell will work on another manufacturer’s drive just fine.
Many incarnations of GP9s and F7s in HO are copied directly, or not-so-directly, from Athearn’s offerings. Here’s what I know for sure will fit:
These are the shells that will fit the Athearn GP7 mechanism, either straight across or with slight shell modification:
Athearn GP7/9 shells regardless of year manufactured
Lionel Virginian rectifier from the late '50s (rare, and also available in other roadnames)
Lionel GP9 in late '50s and mid '70s incarnations
Cox GP9M (copy of the Athearn body with a new low nose)
Model Power GP9 lownose (copy of the Cox)
Walthers GP9M (copy of the Cox)
Lionel U18B (made to fit their GP9 frame)
These are the F-unit shells that will directly (or with slight modification) fit on the Athearn F7 mechanism:
Athearn F7A and F7B shell regardless of year manufactured
Revell F7 (their own tooling)
Tyco pre-1975 F7A and B (direct Athearn clones)
Mantua Deluxe F7A and B (same)
Cox F3 (favors the Athearn nose, windows, and roof contours, but with new sides and detailing)
Stewart F3/F7/F9 (with slight modification)
Intermountain F3/F7/F9 (engineered for the Athearn F7 frame)
Highliners F2/F3/F5/F7/F9 B unit shells (engineered to fit the Athearn frame)
Athearn Genesis F2/F3/F5/F7/F9 (originally Highliners, A units brought to market by At
This is what I know so far, granted they are pretty basic:
Kato/Atlas RS-11, RS3, C425/425, GP7/9 chassis will fit newer versions shell and vice-versa. Same with chassis, the RS-11 and RS3 use the same chassis. Modifications may be needed when mounting new shells on old chassis (I’m trying to find RS-11 or RS-3 chassis, atlas has BN RS-11 shells on sale; I’ve done this with C425s)
P2K GP30 frame can fit under athearn RTR GP35, but the weight needs to be filled down on the sides.
All P2K GP7s, 9s, 18s, and 20s, use the same basic frame. There have been changes to the light-bars, clips, weights and screw hole locations over the years. Modification may be needed. The motor, trucks and drivelines are the same as the GP30.
Atlas U33/36C, C30-7, and U30C use the same frame. The U30C front weight has a lower cut-out for the crew figures. (have a U30C on a U33C chassis). Shells may fit BLI C30-7 chassis with modification (I haven’t tried it)
I’m assuming the answer to this is “yes” - will a Proto 2000 RS18 chassis fit a Proto 1000 RS18 shell?
If somebody else has done it & can tell you about it, that’s great. If not, you may have to do your own research and experimentation. If you’re willing to do a bit of cutting and fitting to allow for the shape of interior components, coupler spacing, etc., then there are lots of possibilities. Just check the dimensions of the shell donor against those of the mechanism donor.
Many years before P2K released its BL2, there was a BL2 made by AHM. Details weren’t great, and it had a mechanism that could charitably called Less Than Ideal. I checked dimensions and determined that a prototype BL2 had a center to center truck spacing of 35’ 0". When Atlas released their early FP7, I discovered that an FP7 had a somewhat comparable truck spacing of 34’ 0". Overall carbody length wasn’t exactly the same, but it was close enough that the couplers came out at a workable distance. The resultant swap created a very serviceable and practical model. I cut out the poorly rendered roof fans and inserted fans from a donor Athearn shell. It looked pretty good if you ignored the incorrect fuel tank details.
Most EMD switchers from SW1 through at least SW900 used a 22’ 0" center to center truck spacing. For the most part, you should be able to swap those shells and mechanisms fairlty freely, although the shorter hood of an SW1 might possibly interfere with the gear tower of the front truck. Truck spacing on switchers from other builders varied widely.
The vast majority of First Generation road switchers from EMD, Alco, and Fairbanks Morse almost all had a center to center truck spacing of 30’ 0". These included GP7 and GP9; RS2 and RS3; and H15/16-44. This jumped to 31’ 0" on the Alco RS27 DL640 and EMD GP20. The earlier RS1 also had a 31’ 0" spacing. Fairbanks Morse H20-44’s were shorter, at 27’ 0"; and Baldwins generally were longer, at 32’ 3".
Truck spacing increased as locomotives got
Another shell swap that works quite well with some frame modification and some slight shell modification is a Tyco/Mantua GP20 shell onto an Athearn GP35 drive. My road units for my railroad are these. (Seven of them for freight and two for passenger.) I found the metal handrail kits and modified Athearn stanchions to fit.
Packer did a very good job of explaining some of the swaps that I know about. Others:
Atlas Master 2 part shells can fit over current Atlas Gold chassis with elimination of the mounting tabs and fusing the shell into one piece.
Athearn GP 38-2/40-2/50 shells can fit onto Atlas Master GP38/40 or Silver/Gold chassis by removing mounting tabs and handrail nubbies from the underside of the shell and slightly chamfering the corners of the Atlas chassis. Light bezels will have to be scratchbuilt. Pilot needs filling in below the coupler box in a way that helps hold the shell onto the chassis.
Wathers P2K shells will fit Stewart/Kato drive frames. They snap right on.
It looks like Intermountain will fit Stewart/Kato frames. I have had both apart and the mounting system are the same. I had no reason to try it, maybe next time.
Another one that I remembered that I have personally done is the Stewart F-unit shells onto Athearn BB drives. The center hole on the sill of the shell needs to be made a little bit bigger and the coupler needs to be body mounted. (The Athearn mount removed.)
One I did around 13 years ago was to use a Athearn BB GP40-2 shell on a Atlas GP38 drive. All I had to do was trim the weight on the Atlas drive.
Since I’m not happy with the colours Athearn applied to a Genesis F7A unit and I bought it anyway to run as the second unit with my BB Athearn F7A (the only one CPR actually ran and only on my railroad) lacking immediate access to an F7B (of which the CPR had many) I’m planning to modify an Intermountain F7B shell available at my LHS. Some previous owner presumably permanently borrowed the drive out of a unit.
Test fitting an Intermountain F7B shell from another unit I have reveals that Athearn did not cast the required notches into their frame to receive the four wedge shaped clips moulded into the fuel tank shrouds Intermountain provides for securing their shell.
On the Intermountain shell these shrouds with clips are a separate plastic part glued to the shell.
Anybody know whether slicing off these four clips will actually allow the Intermountain shell to firmly snap over the Genesis drive? I’d like to know before I ruin a perfectly useable shell. I presume once those clips are gone the shell will no longer fasten to an Intermountain drive or any of the other brands using this clip system.
My LHS also has an undecorated F7B kit and I know how to paint and decal this as another cheaper option. The same modification will be required, removing the securing clips, but at least I would not be sacrificing a usable factory finished shell.
Just btw, the old BB and the much newer and nicer running Genesis run together in consist perfectly. The gearing seems to be the same.
The chassis from the Stewart (now Bowser) Baldwin AS-16 is a good fit into the old AHM/Rivarossi C-Liner.
I did this one, with some added details and new paint and lettering, for a friend…
The C-Liner sideframes are from Detail Associates.
I’ve also found that the old Varney (also now Bowser) cast metal boilers for the Varney “Casey Jones” 10 Wheeler and the Varney 2-8-0 “Old Lady” are, with a couple of minor modifications, a good fit on the chassis of Bachmann’s old time 10 Wheeler.
Here’s the Bachmann 10 Wheeler…
…and the Varney boiler…
…and the modified Varney boiler…
…and the boiler (with a cab from a Bachmann Consolidation), on the Bachmann chassis…
…a few added details…
As always, great photos and useful information. Thanks.
Early Genesis F7A to F7B. Not DCC ready and pretty tight in there for anything but a small motor decoder without a bit of milling so it will stay DC for awhile yet.
I actually want an F7B so need to fit a different shell. The Genesis paint colours are incorrect for CPR (leaving aside the fact that the CPR didn’t buy any F7A units). The red is more oxide or boxcar red than Tuscan Red and the grey is too light. Presumably the Genesis B unit will be as bad.
So, I know that an Intermountain shell will fit the Athearn drive because I tried it. The locking tabs need to be removed but otherwise it’s a perfect fit. I can buy an undecorated kit to assemble and paint using the same paint and decalling to match my ancient BB F7A or I can buy a decorated shell nearly matching.
Either option will need the four locking tabs shaving off the inside of the fuel tank shrouding in order for the Intermountain shell to fit the Genesis drive.
I’m reluctant to modify a perfectly good decorated Intermountain shell but it would be the easier and faster option.
Which would you do?
Decision made for me. Someone bought the decorated shell. I bought the undecorated kit today. I can match the colours of the F7A perfectly since I’ll be using the same Tamiya paint. Same Black Cat decals.
Shaving off the four wedge shaped clips will be also easier since those parts glue on separately.