What couplers should I use? This question has been asked by large scale railroaders over the years. They all want to standardize, and there are a large number of couplers out there. It seems that each large scale manufacturer has its own version of a coupler, and as usual, they don't all couple with each other. In this article, I am going to cover the ones that I have had experience with. What you choose for your rolling stock is strictly up to you.
The only "standard" G-Gauge coupler appears to be the Hook and Loop introduced by LGB. These are found in the box for almost every large scale locomotive and car. They are big, ugly, and look nothing like the prototype. Bachmann equipment comes with couplers having hooks and loops at each end. LGB has a hook at one end and a loop at the other end, which means that you had to turn your cars so that a hook was available to mate with a loop.
If you are interested in "operations" where you are dropping off and picking up cars, these are not for you, as you cannot push cars into sidings without the couplers latching. They seem to work well on rough and unlevel track where you just want to keep your train running in a loop.
The knuckle coupler is what the prototype uses, and what a mess the manufacturers have created with these. Let us examine each one to see their good and bad points. Most available knuckle couplers operate by a pin being pulled from the top to unlatch them. The Aristo and Kadee couplers are the exception to this rule.
LGB Knuckle Coupler: These couplers work well, and when coupled will not open accidentally. The pin that opens the coupler may stick when new, and often requires some burnishing so that it drops freely. Once it is burnished, it should be lubricated with either graphite or Teflon lube to keep it moving smoothly. These couplers will fit almost all large scale products with only minor modifications. The downside is that they are not very prototypical looking, and are very expensive. I have changed out all my LGB knuckles for Kadee couplers as part of my personal standardization program. The LGB couplers sold well on Ebay.
Aristo Knuckle: This coupler is a good one to standardize on if you don't need remote uncoupling. They work will on long trains and uneven track. The uncoupling pin is located on the bottom, and cannot be operated from the top of the coupler. It is chunky and will couple with Kadee couplers (The "G" not the "#1"). Lately the coupler quality has suffered, and there have been complaints about them pulling apart. Quite often you really have to bang your cars together to get them to couple. Seems like as they age they become less reliable.
Aristo Kuppler: This coupler was announced four years ago, and has yet to surface. They apparently are made to mate with Kadee couplers, but not with older Aristo couplers. The operate by a pin being pulled from the top to unlatch, and even have a hole in the top of the pin so that you can hook them to an uncoupling lever like the prototype uses. They are meant for body mount, but at $10 per pair, you will save money by using Kadees.
USA Knuckles: I do not have a lot of USA cars, so I converted them to Kadee couplers. These couplers do not mate with other knuckles on the market. People that standardize on these have mostly USA cars on their roster. They do not couple with Aristo knuckles at all. They are also not set a standard height as measured by other manufacturer's products. They are in fact low when checked by a Kadee coupler height gauge.
Bachmann Knuckles: These couplers are not as reliable as the other brands mentioned. The easiest fix for these couplers is to glue them shut as they have a tendency to open for no apparent reason. The couplers mount low in respect to other brands. I don't recommend using these unless you have all Bachmann rolling stock. The couplers used on Bachmann Spectrum products mount at the proper height, but are "clunky" and do not look prototypical because of the height of the coupler itself. These couplers have a pin that pulls up to open them, but like their smaller brothers, I have had to use CA glue to keep them closed during operation, especially when running on the Sundance Central during shows. The one thing that have going for them is they are made of metal and are very durable.
Accucraft Coupler: I was introduced to these couplers when I was a member of the Sundance Central. These couplers are metal and uncouple by pulling a pin upward. The pin also has a hole in it, and I have hooked chain to the pin and to a working uncoupling lever. They are prototypical and rugged. I have never had a problem with these. They are perfect for 1:20.3 scale rolling stock and a little large for 1:29. They couple well and are similar in size with Kadee "G" couplers, and do not uncouple unexpectedly. They only uncouple manually but are definitely worth a look.
Kadee Coupler: If you are into operations, or want a rugged metal coupler that will stay coupled and works with most other knuckles, this is the one to consider. The Kadee comes in two sizes "#1" or "G". The "#1" is closest to scale for our 1/29 locos and rolling stock as it is the smallest of the two. The "G" coupler is close to the size of all the other knuckles listed above. I have pretty much standardized on these because I used them extensively in HO and was very happy with them. They have a delayed feature that swings them to the side on a cheap uncoupling magnet, which allows them to be pushed into a siding without recoupling. The secret is a metal "gladhand" that hangs down and works with the magnet set between the rails. I have had a great deal of success with these in my garden layout, and will continue to slowly convert my Aristo rolling stock as the Aristo couplers it break down. I have changed out all my LGB, Bachmann, and USA couplers to Kadees right out of the box. Kadee makes numerous models of their coupler, and their website has instructions and diagrams set up to show you what model coupler should be used for what cars or locomotives. Can't find an application listed? E-mail them and they will send you a quick reply to help you out.
There you have it, a short lesson on couplers for large scale trains. Standardize on one, and you will have trouble-free garden railroading.
If you like to run trains in continuous operation with little switching, the hook and loop will provide excellent service at minimal cost. Their appearance is less than prototypical. If you run mostly Aristo equipment, then standardize on the Aristo coupler. If you run mostly Bachmann equipment, then you should probably use the supplied hook and loop couplers as the Bachmann knuckles uncouple by themselves too often. For more realistic operation involving a lot of switching, either the LGB or Kadee couplers will provide excellent service.