About Sharon Couplers - The Prototype

There are a lot of common misconceptions about what a Sharon coupler is. The photo to the right shows a typical Sharon coupler. Nowadays, it is very rare to find a Sharon coupler outside of a museum. Notice that the thumb side of the Sharon coupler is very different from the type E coupler that you are probably more used to seeing. Sharon couplers all have three ribs on the thumb side: a horizontal center rib, and upper and lower ribs that separate toward the front of the coupler. The type E coupler (and its type D predecessor) have four square holes here instead.

"Sharon" refers to a very popular coupler design that was manufactured by several casting companies over the years. The Sharon design was not a type E or a type D. It was simply a Sharon. The design predated the type D and E. Lots of other designs did as well - Janney, Tower, Alliance, Gould, Climax, etc, etc, etc. The Sharon coupler was almost certainly the most successful in this group. All these couplers where interoperable because they adhered to the same profile - the MCB5 profile. Unfortunately, interoperability is where commonality ended. Interchange required repair shops to maintain spare parts for 20ish different coupler designs. The eventual standardization to the type E resolved this problem.

The Sharon (and other MCB5 couplers) mate just fine to ARA/AAR style couplers like type E (and D, F, H, SE, SBE, etc.) couplers that use the MCB10 profile. The picture on the left demonstrates this fact. You can also see differences in the MCB5 and MCB10 contours in this picture. Notice that the face the knuckle pushes on is flat on the MCB10 contour, but angled on the MCB5 contour.

Sharon couplers lasted a long time. Some new standard gauge passenger cars were still being built with Sharon couplers into the mid-1930's (maybe even later). Industrial centercab diesels used these as well into the 1950's. Presumably, these couplers were much less expensive than the type D and E counterparts so they continued to be used for a long time in applications that did not require interchange between railroads. When exactly were they outlawed for interchange? If anyone knows this answer please contact me with the reference.

Sharon couplers like other MCB5 designs were weak compared to the AAR style couplers. They worked great for narrow gauge railroads though and continued to be used there till the very end. Not all narrow gauge railroads used full size couplers. Some used half or three quarter size couplers. Some stuck with the link and pin arrangement. Many of the narrow gauge "big boys" used full size couplers though. Narrow gauge roads in the western US used full size couplers pretty much exclusively. The ET&WNC in the eastern US also used them. Most of these full size couplers were MCB5 designs like the Sharon. In fact it's probably safe to say that most of these couplers were indeed Sharon couplers.

About Sharon Couplers - The Models

Sergent Engineering Sharon couplers are faithful metal reproductions just like our other couplers. They operate pretty much just like the rest of our couplers and they are compatible with the rest of our more modern AAR couplers like the type E. These couplers are provided for modelers whose focus is on the pre-1940 era and narrow gauge roads. The Sharon coupler includes a shallow slot on the top of the coupler where a wire loop (not included) can be attached to represent a pull-pin since most Sharon couplers were top operated.

The Sergent Engineering Sharon couplers are die cast just like our EC87 couplers. Overall, the Sharon couplers are small compared to the Sergent Engineering AAR style couplers. Die casting was a requirement in order to achieve the tight design tolerances necessary for the tiny models. The die casting process also means the Sharon couplers can be offered at a lower price compared to investment casting. Prices are comparable to our EC87 couplers.

Sharon couplers are offered in kit form only. See instructions for RC87K here.

The Sharon coupler design is offered with four different shank styles:

  • The compatible shank coupler (RC87K) is suitable for old time standard gauge rolling stock.
  • A standard narrow shank version is available both with (RN87K) and without Accurail (RNC87K) draft gear boxes. These standard narrow shank versions can be adapted to both standard gauge and narrow gauge rolling stock.
  • A slightly shorter narrow shank version (RNB87K) is offered specifically as a drop-in replacement for Blackstone Models rolling stock. These couplers do not include draft gear boxes.
  • Finally, a version that may be adapted to steam locomotive pilots and similar applications is available that includes an investment cast coupler pocket.

    HOn3 modelers will be happy to know that the Sergent Engineering Sharon coupler will mate with the KD 714 couplers that most HOn3 modelers use today. It's not particularly pretty, but it works. The couplers are not compatible with the MicroTrains couplers found on some HOn3 equipment.

    There are several design differences in the Sharon coupler verses previous Sergent Engineering couplers.

  • The locking mechanism for the Sharon coupler is improved some over that used for its ARA counterparts. As a result, the lever attached to the knuckle has taken on a much more realistic shape than that on the ARA couplers. This also results in an operational requirement for the Sharon couplers that one knuckle should always be closed for reliable coupling. In practice, this isn't much of an issue, but it is something to be aware of.
  • While these couplers use the same 1mm ball as other Sergent Engineering HO scale couplers, the friction spring is about 10 time lighter. This allows the couplers to better self align during coupling and is very important for very light narrow gauge rolling stock. Its best not to use the stronger springs on the Sharon couplers.
  • Narrow shank style couplers have traditionally been available only with the Accurail draft gear box. Since most HOn3 applications don't need the box, couplers are offered minus the draft gear box.