A train needs couplers in order to stay together to move the freight down the rails. Our model trains need functioning couplers to successfully complete a similar task. People frequently ask me what couplers are used on the HO scale Wheeling Freight Terminal. Since I just replaced couplers on several models, it seemed like a moment to share in a blog post. Click on any image here to review a larger size.

Back in the late 1990s, semi-scale couplers were being released by a few manufacturers. Kadee had been a long-time leader in this area. They introduced their #58 coupler which was smaller than their traditional #5 coupler, but still a bit larger than the prototype hardware. I bought several sets and installed them on quite a few freight cars.

At about the same time, Sergent Engineering released a true, scale-size working coupler but it was not compatible with the Kadee couplers. Most of my equipment at that time was in use on a club layout, so compatibility was an issue.

Then I noticed Accurail had a scale-size coupler available, their Proto:HO coupler. It was designed to reflect the Type E coupler design and it had a coupler box that looked like a prototype gearbox. I bought a few pair and liked how they looked and functioned. As I became focused on modeling 1926, these became my coupler of choice.

Here are the basics. The couplers are a split shank style with a pivot point closer to the freight car end sill. Two screws are provided to mount the assembly to the freight car. Trip pins for magnetic uncoupling are also provided but I chose not to install these. The drill bit and drill template are separate but important for many installations.

Parts are removed from the sprue with a little extra that is sliced away with a sharp hobby knife. The toothpick in the image above is pointing to the excess. The dental probe points to a small sliver of flash that needs to be removed so these work properly. A slice and a couple of scrapes removes the material easily. I bought my Accurail Proto:HO couplers in bulk nearly 15 years ago, so newer production may not have this small bit of flash to remove.

After the small bits are removed, a graphite stick is used to lubricate the interfacing parts. A simple pass with the graphite stick on each side of the coupler shanks near the pivot point does the job.

The couplers are assembled in the gearbox and ready to mount on a freight car.

Many of the recent Accurail freight car models have an extra set of holes to install these couplers. Just the week, I discovered some Atlas models have these mounting holes, too! A few of the Atlas 36-foot refrigerator cars are in my freight car fleet, so upgrading them with the Proto:HO couplers was easy.

The reefer underframes are cast metal but the holes are tapped and ready for the small 0-80 screws.

In just a few minutes, two out of three reefers had new couplers installed.

Most of my 1926 freight car fleet is equipped with the Proto:HO couplers. 10-15 car freight car strings are pushed and pulled all through a typical operating session with minimal problems. These couplers mate well with the Kadee #58 couplers that are in use on several freight cars. There were some problems with compatibility, but this was between two types of Kadee couplers, the #58 semi-scale couplers and older 35 couplers. The older Kadee #5 couplers were replaced, or those freight cars were retired, recently which ended those difficulties.

As a prototype modeler, I try to build models to reflect the real thing. Couplers are part of the model and deserve attention. The Sergent Engineering couplers are really nice and would probably be my standard if I were starting over. The Accurail Proto:HO couplers offer scale size, narrow gearbox, a closer coupling between cars, and less play when coupled together. Some installations are challenging, but they make the completed resin freight car kits look even better.

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22 thoughts on “Couplers”

  1. Hi Eric,
    Nice review and tutorial.
    Does the closer coupling distance between cars materially negatively impact their ability to negotiate smaller radius curves? Say an 18″ radius curve?

    1. Thanks for your comment, Art! I don’t know about the close coupling on 18-inch radius curves. My tightest layout curve is 22-inches and I do not see ay problems there. Please note the Proto:HO coupler pivot point is closer to the end sill than the Kadee products. This positioning may enable easy performance on tighter curves. – Eric

  2. Hi Eric,

    Thanks – this is an interesting report.

    I tried the larger style Accumate couplers when they were fairly new in the market, and was disappointed because they tended to ‘split’ open when on cars in a long cut that was being shoved. On my layouts (I’ve had a couple), I have often had to shove cuts of cars longer than 15 cars, so I’m wondering if the problems I encountered were due to the larger Accumate coupler or the longer cuts being shoved. I would be interested if you could try shoving more than 15 cars and report on the results.

    1. Todd, my layout does not have any grades to experiment with different forces on the couplers. On occasion, I do see the freight house crew pulling and pushing more than 15 freight cars in order to clear tracks and spot inbounds. I have not seen any problems with the Proto:HO couplers splitting open and failing while in use. I think the extra graphite step may help keep the parts springing back into place. I’ll play around with a 25 car train and shove it through the two main curves and a few track switches. – Eric

  3. I have had issues with these couplers on long and heavy trains on a club layout, not as much on my smaller home layout. They tend to flex under tension, it seems. They are economical, though, and do look good. I have not had any compatibility issues on my home road, where there is much switching action. Nice fleet of cars….

    1. James, are you certain the couplers are the Proto:HO scale couplers? I’ve heard similar comments about the Accumate couplers that come with Accurail and Atlas freight cars. The Proto:HO couplers are available separately. I’ve had to point out to several people that Accurail makes two types of couplers. – Eric

  4. How easily do they uncouple with a pick (bamboo skewer, little screwdriver, etc.)?

    Also, can you share a picture of the underside of one of the Atlas 36′ reefers? Try as I might, I have yet to locate one online (an image, that is) and I have no LHS close by to look in person. I’m guessing they come with a K brake, but I’d like to know for sure.



    1. Galen, I use bamboo skewers for uncoupling. The smaller diameter versions work fine. I’ll send you a photo of the underframe. They do have K brake systems installed. – Eric

  5. Like you I love the Accumate coupler boxes. Sergent makes a coupler for them. 0-80 flat head screws hold well and look better than those supplied. While the Accumate Proto couplers look good, I find the coupling/uncoupling of these couplers less than satisfactory. Coupling forces seem high and neither magnetic nor pick uncoupling is always perfect. I’ll stick to my 1960’s KaDee711 style – ugly and hard to install but excellent operation.

    Art: With the close coupling of my 711’s 22 inches is minimum radius for maintaining car separation. At 18 inch radius corners will touch.
    Dick Bradley

    1. Thanks for your comment, Dick! There are installations when I would prefer a flat head screw. I guess I should check with McMaster-Carr and order some. Before installing, I usually hit the knuckle face with fine sandpaper to remove the mold parting line. I forgot to mention that point. My Proto:HO coupler experiences have been positive. I find the Kadee #58 couplers do not center well and often need a nudge with a skewer to line up for coupling. I haven’t noticed difficulty with Proto:HO couplers joining at a slow speed and I hit the skewer points with sandpaper to remove roughness or irregularities. They work well for the crews. – Eric

  6. Great article. I am torn between these and the Sergent couplers. Starting over in the hobby and with no club any where within 100 miles compatibility with other brands is not much of an issue.

    1. Jim, use a small layout as a test bed for these type of products. Since the Sergent and Proto:HO couplers use the same gearbox and mounting screws, it would be easy to change over once you have made a decision. – Eric

  7. I bought 2 pr of KD 58’s when they came out – they worked fine. So I bought 100 pair.

    Then I discovered Accuscale. These daus, if the kit has a built-in KD 58 coupler box (like the Westerfield S-40-1 stock car) I use the KD 58; if not I use the Accuscale. They work well together, take 18″ radius curve and near 5% grades (a mis-measure), do swizzle-stick uncoupling with a variety of sticks. I think the Accuscale look a tad better than the KD.

    I am glad I made the switch – but I still have a bunch of KD 58s after converting about 98 cars and 12 locomotives to scale couplers.

    Dave A.

  8. After reading your Blog about these Proto:HO couplers I installed a pair in one of the new Accurail box cars and I have to say I’m very impressed. They uncouple easily with their pick device and they look great. The only problem is that there now seems to be a shortage. Thanks for posting this.

    1. Thanks for the comment, Nevin! I’ve been in touch with Dennis Storzek at Accurail about the Proto:HO couplers. More are coming soon. He wants to finish work on an upcoming model before running the molds for more Proto:HO couplers. I’m glad demand is growing for these fine couplers! – Eric h.

  9. Hello Eric,

    You say that Accurail produces two different couplers, Accumate and Proto:HO. Your article, I think, describes you use of the Proto:HO coupler, is that correct?

    When I look at Accurail’s website under both “Parts” and “Couplers” I only see the Accumate coupler. Where is the Proto:HO coupler shown?

    I’d like to buy a couple of the Proto:HO couplers, if that’s the one you describe and like. Since I only saw the Accumate couplers on Accurail’s website, where they say that coupler is out of stock, I e-mailed them asking when they plan to resume production. That was about a week ago and they haven’t responded yet. I’ve also telephoned several times, but no one answers. I understand from their website that they don’t have a sales staff, so answering their telephone is hit or miss.


    1. Chuck, the Accurail couplers have been rebranded since this 2017 blog post. I see them at the top center portion of the Parts page listed as Scale Size Accumates Coupler w/draftgear box. They have been out of stock for awhile. I sent an inquiry to as I’d like to purchase 100 more sets for future models. You might be able to find packages in a hobby shop under the older Proto:HO coupler name. I’m sure they will be available again. – Eric H.

  10. The couplers are back in stock as of about 2 months ago I purchased a lifetime supply for myself.
    I also have used these couplers since they were introduced and have no complaints.
    The couplers mounted in there scale size draft gear box are a challenge coupling on a curve at times
    due to the narrow swing of the coupler in the narrow box and the split shank but well worth it.
    The draft gear box is very nice and long enough to mount directly to the bolster and if needed you can
    trim quite a bit off the rear of the box which helps with challenging installations.
    I use these on everything including my steam and diesel witch makes for quite a challenge at times.
    When mounting the boxes I use countersunk screws so they are level with the box when finished.

    Edward Rethwisch,

    1. Thanks for your notes, Ed. I admire your freight cars and have noted your Accurail coupler installations. I think Accurail ran production on these couplers in late December 2021 and at this March 11, 2022 posting, they have few in stock. It seems their scale coupler popularity is growing! – Eric H.

  11. Eric,

    Thanks for this posts that I’m reading 5 years after it was originally posted!!

    I have been toiling back and forth as alot of us do… KD 58’s, sergent, and i just noticed these accumates. I started to go down the Sergent road ..but no sooner I started they are out with maybe a few guys looking to carry the flag.

    I have a relatively small fleet at this point so any wholesale change wouldn’t be difficult. I really like the idea of this accumate with the scale draft box. My layout in the works is based on Late 30’s.

    I guess Im sort of leaning toward these scale accumates.. but was sort of holding out to see what happens with Sergent…

    So the point of my posts is to seek your thoughts on do you see any roadblocks or stumbling blocks I might encounter with full switch over to the scale accumates..?

    Thanks for all you do!

    1. Thanks for visiting the blog and commenting, Brian. Since he Sergent and scale Accumate couplers use the same couple gear box, it would be easy to switch out those components. I’d change out the couplers on three or four cars to see how you like them. I’ve been quite satisfied with their performance.

      As I understand it, the Sergent files are now open source. Some people are producing them in small batches. There might be a discussion list on that you can join to see where those couplers are headed. A Google search should bring it up. Best of luck! – – Eric H.

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