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My latest creation is yet another oddball locomotive never before seen in O Gauge-- the Chicago and North Western's "Crandall Cab" E8. The CNW found themselves in a tight crunch for passenger motive power in the 1970s, and their stopgap solution was to rebuild cheap old E8 B-units into commuter train cab units. Here's a neat article that I found online that documents the Crandall Cab. The result was a distinctive triclopean cab welded to the classic "covered wagon" body.

IMG_20240408_164252393

This build started off life as a MTH Railking E8 diesel from an AA set. This frame is far from a prototypical scale sized E8 frame, but it's the closest thing that I have in my collection, and I happened to have it sitting on the workbench already.

001 Donor engine frame

This is a case of making lemons from lemonade-- my E2 "City of San Francisco" needed a body-off rebuild to address some persistent problems, so while I had my prized custom in pieces on the workbench, I borrowed its electronics for a side project.

IMG_20240315_163507998

I already had the CAD files for the frame and PS2 board guts mockup that I used to develop the E2 in Fusion, which was another time saver.

002 mth railking e8 ps2 chassis mockup

Over the course of a week or so, I hashed out the CAD drawings for the Crandall Cab. The conversion kit consists of a 3-section body and a new front pilot.

003 railking crandall cab resin body iso drawing

The first and simplest part of this model was the pilot. I decided to go with a truck-mounted pilot for better track handling. I took bracket measurements from one of the original E8 pilots and then designed a new pilot. Bolting the new part in was easy enough reusing the original screws.

004 new pilot for crandall cab

After a couple days of printing, I had the first version of the new body together. The three sections looked good at first, but as any compulsive tinkerer knows, things never go QUITE right the first time.

005 prototyping crandall cab fit on frame

I made the new screw bosses for the front section a little bit too short, which caused the cab section to slope downwards and bind up with the new pilot. I realized just as I tightened the last screws how much of a problem this would cause.

006 setting clearance between new pilot and body

Adding a little stub to the screw bosses was a 5-minute fix on the computer, but reprinting the cab section took a whole day. The good news is that the second version of the Crandall Cab was just about perfect!

007 track test of first production kit

Here's a look at the back of the Crandall Cab. You can see the grilles printed into the sides of the model; these made the body sections easier to print, are reasonably strong and I anticipate they will look very nice with a mesh grille glued against them from the inside.

008 clearance between vestibules

I'm happy with how the Crandall Cab came out, but I have finally managed to repair the E2 (figuring out the electrical and mechanical problems that have plagued it since 2022!) and am anxious to get it back into service. Before I take apart the Crandall and box it up, here's a video of the new engine going through the paces on my layout.

Hope you enjoyed reading along!

Attachments

Images (10)
  • 001 Donor engine frame
  • 002 mth railking e8 ps2 chassis mockup
  • 003 railking crandall cab resin body iso drawing
  • 004 new pilot for crandall cab
  • 005 prototyping crandall cab fit on frame
  • 006 setting clearance between new pilot and body
  • 007 track test of first production kit
  • 008 clearance between vestibules
  • IMG_20240315_163507998
  • IMG_20240408_164252393
Last edited by Trainguy Ken
Original Post

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My latest creation is yet another oddball locomotive never before seen in O Gauge-- the Chicago and North Western's "Crandall Cab" E8.                                                                                                           

OK.......let's see.....CREATIVITY......COMPUTER SAVVY.......INVENTIVENESS........MECHANICAL  and  ELECTRONIC ENGINEERING.....etc., etc

Great fun work Ken.   thanks for sharing sir.

@coach joe posted:

I don't know how I missed this until today.  Another unique piece for your railroad.

OK.......let's see.....CREATIVITY......COMPUTER SAVVY.......INVENTIVENESS........MECHANICAL  and  ELECTRONIC ENGINEERING.....etc., etc

Great fun work Ken.   thanks for sharing sir.

Thank you everyone for the kind words!

@NHVRYGray posted:

Ken, do you know if the width/ height is same as a scale B unot?

Is this a resin print, looks like it?

Could you modify the file easily to be just the cab, that way it could be spliced to a scale B.


The width and height of this Crandall body are very close to scale. The variable factor would be the height of the frame and trucks of the donor locomotive-- I'm not sure if scale E8s would be quite the same height as the MTH Railking E8 frame that I used, particularly since the Railking trucks themselves are underscale.

Yes, this is a resin print-- I picked up a resin printer last summer and have been using it quite heavily for the past 6 months. I still use good old filament for mechanical parts like the Crandall's pilot, where flexibility and strength is more important than surface finish.

It would certainly be possible to make a conversion kit containing just the Crandall's cab and the new pilot-- that is how the prototypical Crandalls were made, as is clearly evident from the paint-shop photos. Of course, that would require taking a saw to a fully painted and detailed locomotive body, which is a bit more involved than backing out some the screws and dropping the frame out. To make things more complicated, most B-units that I've seen are dummy locos, so you'd either have to cut up an A-unit or add motor trucks to a B-unit. I have some ideas for how to design a full-scale body kit if there's sufficient interest.

Congratulations, Ken.  I am pleased to inform you that your personal record has been awarded ten merits for ingenuity and expertise in creating computer-printed car bodies for E2A and B, as well as C&NW Crandall Cab E8, O gauge model locomotives.  

While up to thirty demerits may be assessed for any incident of rules violations, we are constrained by the Brown System of Discipline from awarding more than ten merits at one time, and then only for truly exceptional performance.  Merits are awarded only upon approval by the Vice President - Mechanical or the Vice President - Operations.  Were it not for the aforementioned constraint, your work would have earned you ten merits for the E2's and an additional ten for the Crandall Cab.

Last edited by Number 90

One of my customers was kind enough to lend me a MTH Premier E8A from his collection so I could design the full scale sized Crandall Cab E8. She's a mighty big locomotive!

0065 prototype shell build

Dismantling the donor frame was easier than expected-- four body screws and 1 connector harness. This particular locomotive has compact Protosounds 3.0 boards which makes for a relatively roomy interior. The original headlight brackets won't line up with the new shell without heavy modification (which I won't risk with a borrowed locomotive), but the old cab interior works surprisingly well.

001 Guts of Premier E8 donor engine

I started by making a mockup of the electronics in Fusion 360.

002 mth scale premier e8 frame with clearance mockups

Once I had the mockup, I superimposed the semi-scale kit over the top of it and started cutting, fitting and tweaking. After quite a bit of CAD work, I had a four-piece body that was the proper scale length. I colored the sections so you can see where the divisions are. This is necessary to squeeze the 18" long body into my printers.

mth scale premier e8 MK4 body assy

Here's a close-up of the Crandall cab itself with the new pilot added. This does have a truck-mounted pilot, based on the semi-scale model, but modified to fit the larger Premier scale trucks.

mth scale premier e8 frame closeup of improved cab

The whole kit, printed out in UV-cured resin (with the pilot in sturdy ABS), looks like this. The front and rear sections screw into the E8A's original screw holes, while the two center sections tab in between them. The pilot reuses the original truck screws to mount in place.

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Here's what the locomotive looks like fully assembled onto that Premier E8A frame.

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Here's a view from the rear. The PS3 engines have a panel with all of the run/pgm switches on them that is accessible through the open vestibule door in the kit's rear.

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Here's a video of the rebodied locomotive running on my layout. Man those PS3 sounds are nice!

Although I developed this locomotive conversion kit for a specific customer, I know that several others have expressed interest in this project, so I'm going to print a couple of these. Please send me an email if you would like to reserve a kit for yourself.

Attachments

Images (8)
  • 001 Guts of Premier E8 donor engine
  • 002 mth scale premier e8 frame with clearance mockups
  • mth scale premier e8 MK4 body assy
  • mth scale premier e8 frame closeup of improved cab
  • IMG_20240523_165050142
  • IMG_20240523_165057245
  • IMG_20240523_171427307
  • 0065 prototype shell build

One of my customers was kind enough to lend me a MTH Premier E8A from his collection so I could design the full scale sized Crandall Cab E8. She's a mighty big locomotive!

IMG_20240523_165057245



, I know that several others have expressed interest in this project, so I'm going to print a couple of these. Please send me an email if you would like to reserve a kit for yourself.

My two cents Ken ,  possible use of household window screen could be used for the ventilation slats glued inside of the body !?!   🤔      There is plastic screen , metal screen and if I remember there was a fine screen on the Amazon site.

Everything is looking good Ken

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