OO Gauge Fixed Link Coach Couplings – Part 1

At long last my freight couplings for British OO rolling stock with NEM sockets are now available, so it’s time to share with you my designs for coach couplings.  You can find the freight couplings here.

Early British coaches had similar coupling to the freight 3 link.  They each had a hook and a chain, but because passenger stock needs to be smooth, the chains had a screw section in the middle. This worked by having the locomotive push two coaches together so the buffers compressed, then the chain was hooked over the hook and the screw tightened up.  When the locomotive releases the pressure the buffers can never fully un-spring.  This means there’s never any slack which would cause the train to snatch and jerk, as that’s not ideal when you’re sitting down to lunch!  Below is an example of a locomotive coupled to a coach with a screw link coupling.

Later coach stock adopted the knuckle coupler, very similar to the standard system used in the US. The difference is the knuckle can rotate around the hook so both systems could be used.  The knuckle coupler would hang down allowing normal access to the hook.  When needed, the knuckle coupler was lifted and held in place by a pin.  In the picture below you can see this arrangement on a BR Mk 1 coach. (Picture by Chris McKenna from Wikipedia)

The pin also held the knuckle down when not in use to prevent it from swinging.  This has also been implemented on locomotives.  You can see it on the front of the BR Class 91 locomotive below. (Picture by Chris McKenna from Wikipedia).

Modeling this can done and, with newer models now having the NEM sockets, different couplings can easily be exchanged.  A plug-in Kadee knuckle coupler is available for the NEM socket and it’s a good way to connect coaches.  However as with the freight stock, if you have rakes of coaches which you want to stay permanently coupled, adding Kadee couplers comes with the risk of separation plus the expense of adding one to each end of every coach.  Bachmann make a coupling designed to be a fixed link between coaches which looks like vacuum pipes hanging down.  Again this is a good idea but what if you run trains at exhibitions or like to swap the trains on your layout?  Picking up 5 to 10 coaches all linked together is a bit tricky.

So how is 3D printing a coupler better than this?  Well, the nice thing about coach stock is they normally have a corridor connection so travelers can move from coach to coach; this hides the coupling.  Therefore the coupling doesn’t have to represent anything, it simply needs to work.

My coupling is just that, simple.

Each has a peg and hole at one end and the NEM fitting at the other.  The two couplers simply overlap.  The height of the peg ensures they won’t come uncoupled but when you want to remove the coach from the layout you simply pick it up.

As with the freight rolling stock different manufactures have placed their NEM sockets in different locations causing the gap between coaches to vary.  This gap will also need to be specific to your layout depending on the radius of your curves.  So to solve this I have made a few options in length.

And unlike the freight couplings there are only a few; five different types in fact.

They can be used in pairs with the same number or mixed together to give any required length.

Next week I’ll share more with you regarding these couplings and some images of them in use.

OO Gauge Fixed Link Couplings – Part 6

As promised in last week’s post I’ve been busy getting all the OO Gauge Fixed Link Couplings ready and uploaded onto Shapeways, and the Short series are now ready to buy.

The Short series will work for the majority of rolling stock and I’ve added a page which describes all the couplings and sample packs in detail, and that can be found here along with the links to buy each product.

The Medium and Long couplings will be available soon.

I’ve been asked if these couplings can be used for coaches as well.  The short answer is ‘yes’, but they are not very prototypical, as coaches normally have different couplers from freight stock.  But don’t panic as I also have a new and simple coach NEM coupler which is designed for exhibition and home layouts.  It will allow close coupling of coaches without the chance of uncoupling on the layout, but, and this is the good bit for exhibitions, when lifted from the layout the coaches separate straight away, making for a quick pack away after the show.  I’ll be sharing this with you, hopefully next week.

OO Gauge Fixed Link Couplings – Part 5

This week’s post will be short as I’ve been busy getting the new OO Gauge Fixed Link Couplings ready for the Shapeways shop.

As well as the sample sets I made available last week (see the post here) Types 1, 2, 7 & 8 are now available in packs of 4, 10 and 25.  As a reminder as to which couplings they are, please see the table below, which you can click on to make bigger.

Hopefully by next week I’ll have the rest up on the site as well.  If there’s a specific combination of couplings you would like please feel free to get in touch.

OO Gauge Fixed Link Couplings – Part 4

This week I have some good news for my OO Gauge Fixed Link Couplings.  All the designing is done and the sample packs are ready.  If this coupling project is new to you, you can read more about it in the previous post here.

All of the different types of OO Gauge Fixed Link Couplings can be seen in the table below.  The main couplings are numbers 1, 2, 7 & 8. These should work for the majority of models.  However as I described in part 2 of this project some manufacturers have set their NEM sockets at different heights so I have also supplied adaptors to cover all situations.

The first fifteen are the shortest and designed to give 18mm between each NEM socket.  Should your layout have tight curves or you have a model with the NEM socket set further back then all the couplings have been repeated for 19mm and again for 20mm.  The extra distance on tight curves will avoid buffer lock which can derail wagons.

Both the 5.5mm Step Up and the Loose 3 Link couplings were a special request from a fellow modeller so I have included them in the range.  Please note that the 5.5mm Step Up will require any existing molded hook to be removed from the wagon but it will put the coupling at a more prototypical height. Also the Loose 3 Link only has the center link loose, both outer links are fixed; this means there will be some slack in the coupling but it’s only good for pulling rather than shunting.

Given how many different types are on the table I’ve made five different sample packs available.

NEM OO 3 Link & Instanter Couplings – Basic Sample

This contains one of each coupling types 1, 2, 4, 5, 7, 8, 10 & 11.

NEM OO 3 Link Couplings – Sample Set

Containing one of each type: 1, 4, 7, 10, 16, 19, 22, 25, 31, 34, 37 & 40.

NEM OO Instanter Couplings – Sample Set

Containing one of each type: 2, 5, 8, 11, 17, 20, 23, 26, 32, 35, 38 & 41.

NEM OO 3 Link & Instanter Couplings – Sample

Containing one of each type: 1, 2, 4, 5, 7, 8, 10, 11, 16 ,17, 19, 20, 22, 23, 25, 26, 28, 29, 31, 32, 34, 35, 37, 38, 40 & 41.

NEM OO 3 Link & Instanter Couplings – Advanced Sample

Containing one of each type: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 & 15.

The packs containing lots of the individual couplings are currently being uploaded and will be available by next week.

A Little Time Off

As is often the case, real life demands that our hobbies get put to the side sometimes. This weekend has been one of those times and work has taken up my spare hours. So this evening I’m having some time off, getting outside to enjoy the summer evenings while we still have them, and reminding my wife what I actually look like! I will see you all next week, have a great one.

OO Gauge Fixed Link Couplings – Part 3

Back in March 2017 I was in the process of sharing with you my designs for OO Gauge fixed link couplings utilizing the NEM sockets; you can read the post here.  However when Shapeways announced their pricing structure change for the FUD and FXD materials this put a pause on the project.  Mainly because under the new pricing structure there is a $1 charge per part on top of the material costs etc.

The good news is I have now redesigned the couplings so they can be 3D printed as one piece but can be easily separated.  I looked at several different ways to do this but each had its pitfalls. Because all of the exposed parts of the couplings have high detail or are part of my flexible joint, putting a connection back to a sprue would mean a rough area would always be at the point where the coupling was cut off.  The other part of the coupling fits into the NEM socket so again any rough areas would prevent the coupling from fitting correctly.

The solution was to add all the couplings to a tie bar with ‘T’ stalks which pass through each coupling, without actually touching it, as shown below.

The ‘T’ head can easily be broken or cut off which lets the coupling fall away from the tie bar.

Although a tie bar could be used at each end of the coupling this proved to be unnecessary as you can see in this actual set of 3D printed couplings below.

I’ve also made some other very small changes or improvements which don’t show up in pictures but should help to make them even better.  I plan to do a few last checks with these latest versions and then I’ll be making them available.

I plan to release them in packs of 4,10, 50 and 100.  There’ll also be a sample pack which will contain one of each so you can do some testing to see which type you need.  This will be affected by the different types and makes of rolling stock you have plus the radius of your curves; tighter curves will need the longer couplings to avoid buffer lock.

I am planning to have them ready for next week, so fingers crossed.