Here's the background

The Illinois Terminal was forced to start using cabooses around 1910.  They built around 45 or so cupola cabooses between 1910 and the early 1940's.  Due to the fact that boxcars got taller and the overhead electric power lines, the need to see better and provide better safety resulted in the IT converting five of these boxcars into bay window cabooses for mainline use in the mid to late 1940's.  The rest were relegated to locals and the like.  American Model Builders has done an excellent job creating a model of this bay window caboose as seen here.  I have already built a model of this.  I have also built two of their Illinois Central caboose kits.  If you are looking for an easy to build laser cut kit for your first build, I would highly recommend their caboose kits.  They literally fall together and have excellent instructions.  You will need some detail parts and trucks, but that is to be expected for these kinds of kits.  

My plan is to backdate the AMB kit by adding a cupola.  The plan is the create a 3D printed cupola using Shapeways as a drop in place into a hole that will be cut into the roof.  The bay window will not be installed and instead, new scribed sheeting will be installed on the sides with new windows.  Other than that, everything else should be the same... the underbody, the end platforms, brake detail, ladders, grab irons all should be the same.  

Getting started...

The photo below shows what comes in the AMB kit.  Starting on the right and working clockwise are the instructions, the resin bay windows, the window screen, the floor beam parts, the roof cover, the inner wall frame pieces, the sub-roof, ladder and detail parts, an included remodified end steps, and the scribed siding covers that go on the basic shell.  

In order to make the 3D print, I want to know exactly what dimensions I'm working with.  Therefore I went ahead and assembled the basic shell, along with the roof frame and the frame that goes under the floor. I plan on adding full AB brake detail. 

The picture below shows the frame dry fitted into the subshell.  

Next will be to get some measurements and create the 3D print. 

3D design

After making some measurements of the model and using the photos as guides, I have come up with this for a cupola.  

A friend who as an expert at all things ITRR is double checking the "look" of it before I proceed.  I have already gone back and double checked for errors.  There are a couple ways to do this.  First, you can remove a "face", the white parts, to reveal the insides.  The insides should all be open with no walls blocking anything off.  The inside faces are all blue.  If there is white on the inside or blue on the outside, there is an issue.  This is what it looks like with some of the big faces off. 

Strange looking, huh.  The other way to check for errors is to upload it to Shapeways and see if it is printable.  This is pretty easy to do.  I just download it as an .STL  file an then upload it and see what happens.  

This is what it looks like.  The image on the left can be rotated and turned around to make sure it is as it is supposed to be.  If there were any problems with it, they would have popped up here.  It also shows a price, so it looks like this will be under ten bucks, which is great.  The next steps will be to add the wood grain grooves.  I also think I might add the four windows for the side body of the caboose, just so I don't have to frame it out with strip wood. 

Progress

I've finished the cupola for the IT AMB kit. 

I've added grooves that are 0.2 mm wide to simulate the wood construction. I've also added the four windows that I will need for the sides of the caboose, two on each side.  I was able to tuck them up and under the roof of the cupola as shown below.  This will hopefully further simply construction. 

I should be able to clip them off, file them smooth, and then glue them into new window openings that I will cut for the sides. I have ordered one from Shapeways and am looking forward to seeing what it looks like when it arrives.  

Sides

Did you consider drawing an insert for the hole in the sides left by omitting the bay windows? Or would the difference in materials be a problem in getting a good finish?

Reply to Graham Line

I am planning on using new scribed siding for the sides.  The bay window literally takes out the middle 1/3 of the side and the windows are also in different places.  Therefore I will put on new scribed sidding and just cut the four new holes for the windows.  

3D print arrived.

The 3D print from Shapeways arrived in the mail today.  This is what it looks like out of the box. 

The above picture shows what the print looks like out of the box.  Everything seems to be in order.  It's hard to see the scribed siding due to the opaqueness of the print.  

The above picture shows the underside of the cupola.  I have included the four windows that will be necessary to go on the sides of the caboose to replace the original windows. 

This picture confirms that the print is correct.  It just fits between the inside of the frame for the roof.  I will have to move one of the supporting cross braces of the frame, but that shouldn't be a big deal.  I seemed to have gotten the curve correct as it matches the curve of the cross braces. 

Here is the last photo, again not showing a whole lot due to the translucent nature of the print. 

Great Project!

Perfect use of 3D printing.  

Great Project!

Perfect use of 3D printing.  

update

Time to take the plunge.  This picture shows the new parts I'll be adding to the AMB caboose kit.  I have cut new sides out of Evergreen 0.040 V-groove siding to match the original sides but to also extend the whole length of the caboose body.  I have also cut out the new windows from inside the cupola (see above).  To clean the wax off I soaked these parts in warm water with some dawn dish soap.  I used a toothbrush to scrub them, and they seem to be clean.  

Layout lines for windows

This photo shows the drawings for the new window openings.  To calculate this, I set up a simple proportion using the photo in the upper right-hand corner.  I measured the distance from the left end of the caboose to the left edge of the openings for both windows.  Then I set up a proportion to the actual length of the car side.  I then added 0.5 mm to compensate for the part of the window that covers the opening.  This turned out to be 8.3 and 43 mm respectively for each window.  The top line ended up being 6.3 mm from the top.  With the upper left corner established, I then marked the opening for the window at 6 mm wide and 7.3 mm tall.  

Update

Here is another picture of the style of caboose I am after. 

This shows the new v-groove siding glued on the sides of the caboose.  Notice how I was lucky and the windows almost matched the opens in the wood frame. 

Here are the new 3D printed windows glued into place. This is the approximate location of where the cupola will go.  

Nice project

Doug,

That is another nice IT project you got there.  Those IT guys must be digging you!

Dave

update

This photo shows the current state.  I have assembled the end platforms with the resin steps glued in place.  I have used a Kadde coupler box that snaps together.  I will use whisker couplers in them.  The subroof shows how it has been modified to hold the cupola.  I moved the brace to the left after trimming the notched part.  I thin used another piece of scrap from the kit to that had the same curve to provide a support for the more middle side of the cupola.  At the top, I have added new trim boards on the top of the siding.  The trim boards in the kit had notches to fit over the bay window that was supposed to go in that spot.  These were made from a wood strip that is a scale 2" by 8".  

update

I'm making progress.  The two pictures below show the curved grab irons on the sides as well as the L shaped grab irons on the end and the regular grabs next to the door. 

The picture below shows the K brake detail I installed.  There are no brake diagrams from these cabooses so this is my best guess from looking around the internet at early K brake piping.  I didn't include the train airline as it wouldn't be seen.  

Give me a call Doug

I have something that you might be interested in.  If I happen not to be here, leave your number.  541-946-8796 in Oregon.

More details

I have finished adding the details on the end of the caboose. The picture below shows how the ladders were formed.  The AMB kit has a way to place the sides of the ladder so that the rungs can be slid in place, glued, and then the excess trimmed off.  

The details I added are as follows. The handrails were formed from brass wire.  The ladders were made from above.  I added drop step grabs on the ends and formed the coupler levers from brass wire and used eyebolts.  

I formed the roof as per the directions then cut a hole for the cupola.  This is the first trial fit.  

Looks very good so far.

I think you are on to a very likely scenario regarding fitting 3D parts to existing wood, plastic or metal kits.  Can make something totally new and unique from an old 'tired out' old kit.

looking forward to you finishing this up and seeing one of your 3D locos tacking it onto the end of a train.

Looking good!

Doug,

Looking good.  I am with Loren, can't wait to see your model painted, decaled, and running behind that class A or class B!

Dave

more progress

I got just a little bit more work done.  The AMB kit has a peel and stick top for the top of the roof.  Then the supports for the rooftop walking boards are glued in place.  The roof and cupola are still removable at this point as it will make painting much easier to do.  The few things left on the list is to add some lead weight, put some L shaped grabs on the top of the cupola, and add the brackets at the bottom corner of the caboose.  Someone asked, the roof will be black and the sides will be a boxcar reddish color.  

getting close

This picture shows the sheet lead weight that I glued to the floor inside of the caboose. 

The picture below shows the L shaped grab irons that I added onto the roof of the cupola.  These are hand bent grabs using a Tichy eyelet.  The only two things left to add are the smokestack and the corner braces below the curved grab iron that appear in the prototype photo shown in a previous post. 

Ready for paint

Ready for paint.  All the details have been applied. 

Prime time...

Warmer weather means I can paint outside again.  I primed the parts of the caboose . 

The roof of the 3D printed cupola has a few lines.  I'm going to try and wet sand the gray primer to remove these lines.  It's kind of hard to see, but its there. 

paint

Paint has been applied.  This is Scalecoat Boxcar Red.  The roof and underbody will be black. 

The newer bay window cabooses had their ends painted a bright red to make them more visible to other locomotives moving up and down the track.