Rapido Telegraph 21

Rapido Telegraph 21 / September 24, 2009

Rapido Telegraph
The Irregular and Irreverent Bulletin from Rapido Trains Inc.  •  Volume 21

Dear Rapido Customer,

This issue of the Telegraph is an exclusive inside look at the trials and tribulations involved in producing the most accurate and most detailed model F-unit possible.

F-Unit nose comparison
Nose comparison – our first test shot needed work!

What happened?

As I mentioned in volume 19 of the Telegraph, the first test shots of our new HO scale FP9A locomotive came back from the factory and obviously needed work.

Bill and I spent some time looking at the model and re-examining our research material and we quickly realized that our drawings of the nose were the root cause of the major problems. They just didn’t accurately capture the feel of the prototype. But these drawings had been done by a professional draftsman and were based on prototype photos, measurements, and F-unit drawings published over time in the hobby press.

The answer was to forget about published drawings and get our hands on some blueprints. So that’s what we did…

EMD Nose
What a nose! Original F7A cab blueprints from EMD

Looking at the blueprints

I had some concerns that the FP9A nose, built by General Motors Diesel Division in London, would be different than the standard EMD nose, as used on the F7A shown above. Bill and I had already discovered that several details – number boards, headlight, pilot – were indeed different. My fears were put to rest by some former EMD employees and dedicated historians. These are a group of F-unit aficionados who kindly offered their feedback and resources in order to help us get this model right.

We were assured by the former EMD employees that the EMD and GMD noses were the same. In fact, many of the panels used in the construction of the noses were prefabricated by outside shops on jigs and then sent to both La Grange and London for assembly. That puts to rest the myth that every F-unit nose was unique…

FP9Au Odd Shot
FP9Au 6309 at Exporail – not a view you see every day

Now the work really begins.

The first step was to go spend some time with an FP9A. Actually it was an FP9Au, rebuilt in 1983. But the nose shape hasn’t changed. Bill took countless photographs and measurements, especially the kinds of things you wouldn’t normally find in published sources. One example is the bottom of the number board, shown in the photo below.

FP9Au Number Board
Looking up at the FP9 number board (The little bump on the grab is where they cut it from the sprue!)

The next step was to send the blueprints, photos and (virtual) reams of notes to Colin and Dennis at the factory. We spent the following four weeks going back and forth correcting the factory’s drawings to be closer to what we thought the nose should be. Every morning we would get new drawings from the factory, and every evening we would send five to 10 (or more) pages of corrections. Below is a typical page of corrections.

FP9A Corrections 1
Correcting the headlight shape

By the third week, our engineering department at the factory had a poster of Bill on the back of the office door and was throwing darts at it daily. Things got really nitty-gritty. Have a look at the comparison drawing below. Dennis sent us cross sections of the model to match the blueprints, and we overlaid them on top of the blueprints to find where there were problems. These drawings went back and forth for two weeks (causing Bill to throw himself into a brick wall on numerous occasions).

F Unit Nose Blueprints
Comparing cross sections: original blueprints in red; model drawings in blue

Cutting a CNC sample

Once we had ironed out the nose contours, it was time to get a sample. Usually, when tooling is made for a new plastic model, the first sample we see is after the molds have been cut from steel and the first “test shot” has been injected in plastic from the mold. By the time we reach this stage, we’ve spent thousands of dollars on the molds. Obviously, we can’t afford to keep recutting the steel until we are happy with the nose shape. So the factory made a CNC (Computer Numerical Control) milled sample of the nose.

CNC tooling sample
Here’s the CNC nose sample for the FP9A. It weighs a ton.

We had finally achieved the correct contours! Now Bill wants his hair back… he had torn it all out. But we weren’t finished yet. The headlight and number boards still needed work, and the FP9A nose door is different from the standard F-unit nose door: it is larger and raised. After Bill had straightened out these details, I worked with Dennis and Colin to get the rest of the details correct, like the pilot, CN FP9A-specific end features, and other bits which still needed improving.

FP9A Pilot
Correcting the pilot details… page 2 of 15.

More than two months after we got that first test shot from the factory and realized that Rapido’s first F-unit model needed work, the FP9A tooling is once again underway. We found some last minute fixes, like the details behind the Farr grills, and thankfully got word to the factory before the corrections were started. We expect new samples next month. In the meantime, have a look at some drawings of our revised and refined HO scale FP9A model.

Note: these images show all of the additional features (grab irons, strobes, stirrup, etc.). Each model will have some of these features included, depending on the road number, paint scheme and era.

FP9 Drawings
Overview of the new nose

FP9 Drawings
Left side, showing optional grabs and stirrup (Actually, you would never have seen these ditch lights with those grabs, but you get the general idea!)

FP9 Drawings
New details behind the etched metal Farr grills

FP9 Drawings
Revised end details, including a grab for the glad hands! (Yes, we are insane.)
(Coupler cut levers removed for clarity.)

FP9 Drawings
Nose overview, from above

FP9 Drawings
And don’t forget the underbody details! (We’ve finished those already.)

Before starting the corrections, we sent our drawings to our F-unit aficionados. And we were very honored when we were told that this may be the best F-unit model yet. But we’ll let you decide for yourself. The order deadline has been extended until well into the new year. Before the deadline, you’ll have time to see photos of our preproduction models and see them in person at the Cocoa Beach Prototype Rails meet and the Springfield Show, both in January 2010. We’ll also have the sample at the Canadian Association of Railway Modellers Copetown Show in February.

I hope you’ve enjoyed this exclusive look at how an F-unit model is created. This project has been an absolute labor of love for Bill, Dan, Dennis, Colin and me, even with its frustrations. I hope that our heartfelt dedication to this locomotive is noticeable in the model. You can read more about our HO scale FP9A project by clicking here. Better yet, call your dealer and reserve one today!

Speak to you soon,


Jason Shron
Rapido Trains Inc.

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