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Built Review
HO scale
Operating Passenger Diaphragm
Passenger Car Diaphragm Kit Opera Window
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by: Frederick Boucher [ JPTRR ]

Originally published on:
RailRoad Modeling

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Operating Passenger Car Diaphragm Kit
Type: "Opera Window"
Part No.: 9400, 9402, 9404

"Opera Window" Type Operating Diaphragm
This review demonstrates the assembly of the HO scale operating "Opera Window" passenger car diaphragm kit from Hi-Tech Details. It is one of seven designs of diaphragm kits the company offers. Three are "Opera Window" kits in different colors.

HTD packs two complete diaphragms in a plastic bag stapled to Hi-Tech Details' vivid fuchsia and black backing label. The label unfolds to reveal 10 assembly steps, a drill-jig template for drilling mounting holes, and an exploded parts view. Hi-Tech Details also offer a for-real "movie" for the diehards to download that animates the assembly process. ( It's about 8 megs in size, so we recommend it only for those with the luxury of a screaming fast connection.

This is a multi-media kit of styrene, flexible rubber or vinyl, and stainless steel striker plates. Each diaphragm sprue is molded in hi-quality warm gray styrene. While they suffer no ejector marks or sink marks, there's some minor flash. There are also hefty sprue attachments to cut off.

HTD guides us to use CA (Cyanoacrylates, i.e., "super glue") to attach the parts; I used Bob Smith Industries INSTA-CURE and it works great on this multi-media kit. Study the illustrations before you start cutting parts off the sprues. You will cut the center bellows free and them immediately attach in to the outer bellows while it is still on the sprue. Cut these free and attach them to the styrene inner striker plate. This piece has a pair of pins and a pair of slots. Cut two of the vinyl springs from their sprue. each spring has a lug that fits into the inner striker plate slots.

At this point I skipped ahead a couple of steps and attached the prongers. "Prongers" are struts that extend from the striker plate to the car end on each side of the bellows. The bottom mounting plate of the pronger has a hole to fit around the pins on the inner striker. The hole was not molded through and required boring with a #68 drill to allow the pin to fit.

Next attach the stainless steel outer striker plates to the styrene inner plates. After that step HTD guides us to use the template to drill mounting holes into the car of your choice with a #68 or 1/32" drill bit. Then attach the third plastic diaphragm part to the car end and test fit the assemblies.

When you are happy with the fit and action, superglue the pins on the springs into the holes drilled into the car ends.

With that the diaphragm models are finished.

Closing thoughts
I took this set to an operating session; the model railroaders who inspected it were impressed and one spoke of how well they work.

HTD does a good job of molding crisp parts with little flash. I'm impressed with the accurate striker slots and spring lugs, as well as the steel strikers.

I appreciate the well illustrated instructions. They are not, I believe, as unambiguous as they could be. Unfamiliar as I am with diaphragms, it took a few moments to figure out that a "pronger" is not a spring. Perhaps HTD could label the parts shown in the exploded view? Fortunately for those with internet access, the instructional video is very helpful!

All in all I am impressed with these diaphragms and look forward to mounting them on operating passenger cars.

Hi-Tech Details
Model railroading is fun and for many of us part of that fun modeling a particular prototype, even during a specific time. Railroads and equipment manufacturers have given us a bewildering number of modifications to model. These are often unique items and not practical for model makers to mass produce or install at the factory. Riding to the rescue are model makers like Hi-Tech Details. HTD offers dozens of parts and kits in 14 categories:

    1. HO Real Deal Rubber Air & Signal Hoses
    2. HO Diesel , Plastic & Rubber
    3. HO Passenger Cars, Plastic & Rubber
    4. HO Rolling Stock, Plastic & Rubber
    5. HO Diesel , Injection-Molded
    6. HO Rolling Stock, Injection-Molded
    7. HO Lineside Structures & Street Detail
    8. Paint & Adhesive
    9. Tools
    10. Sound & Lighting Equipment
    11. Special Direct Only Detail Parts, Molded Plastic
    12. HO Scale Structure Kits
    13. O Scale Detail Parts
    14. N Scale Detail Parts

Please remember, when contacting retailers or vendors, to mention that you saw their products highlighted here - on RailRoadModeling.

Click here for additional images for this review.

Highs: Crisp molding. Metal striker plates, vinyl springs.
Lows: Pronger plate mounting holes needed boring out. The well illustrated instructions are not as unambiguous as they could be.
Verdict: These diaphragms assemble easily, look good, and should work well.
Percentage Rating
  Scale: HO Scale
  Mfg. ID: HTD 9404
  Suggested Retail: $10.95
  Related Link: Animated assembly video
  PUBLISHED: Dec 04, 2012

Our Thanks to Hi-Tech Details!
This item was provided by them for the purpose of having it reviewed on this KitMaker Network site. If you would like your kit, book, or product reviewed, please contact us.

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About Frederick Boucher (JPTRR)

I'm a professional pilot with a degree in art. My first model was an AMT semi dump truck. Then Monogram's Lunar Lander right after the lunar landing. Next, Revell's 1/32 Bf-109G...cried havoc and released the dogs of modeling! My interests--if built before 1900, or after 1955, then I proba...

Copyright 2021 text by Frederick Boucher [ JPTRR ]. Images also by copyright holder unless otherwise noted. Opinions expressed are those of the author(s) and not necessarily those of ModelGeek. All rights reserved.


Very interesting.
DEC 04, 2012 - 11:21 AM
I hope to soon snare a pair of passeneger cars on which to mount and demonstrate these.
DEC 04, 2012 - 12:51 PM

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