Some question about different couplers.

[JCitron]

I've always wondered about this.
Why do some regions use chains links and buffers instead of knuckle couplers?

Is there any advantage to using the chain system instead of the knuckle couplers?

I've also noticed that some regions use buffers and knuckle couplers. Is there an advantage to this system, or is it a transition between the two different systems?

Thanks

John

 

[johnwhelan]

Basically historical, the early systems started with chains then other couplings came later. If you have a lot of chain couplings it's kind of difficult to rip them all out and switch to a different system.

Cheerio John

 

[JCitron]

Thanks John, that would make a lot of sense.

John

 

[Tokkyu40]

A lot of railways started out with link and pin couplers, which require the brakeman to hold a short piece of metal between two oncoming cars and then drop a pin into a hole to lock the two cars together. This was less then popular. The brakeman is the guy with several fingers missing.
America went mostly to the automatic knuckle coupler. Once the faces are set, the two cars can be brought together and the couplers will lock automatically. It's quick and convenient, but allows a certain amount of slack between cars. You can hear the banging rolling up and down the train as the engine slows or speeds up.
England favors screw couplings with buffers. Once the cars have come together, a worker hooks the cars together and screws the coupler down to hold the faces together. This takes longer, but removes almost all the slack so there's less jerking and banging.

Claude

 

[JCitron]

So which method do you think is better, Claude? The screw couplings sound like they make for a better coupling system so the ride is smoother, and the train can probably move faster because there is less drag between the cars.

John

 

[Tokkyu40]

It depends. The screw couplers are smoother for passenger traffic, but probably no better then the automatic couplers for multi-unit trains like in Japan.
The knuckle couplers are faster to operate which is good for switching freight. They're also stronger, so you can run longer trains. 100 cars is common in the U.S. so coupler strength beats comfort, especially for freight.

Claude

 

[whitepass]

Thousands of coupler have been designed, hundreds made and used. The buffers used in the UK are shock absorbers witch are not used in the US as the shock absorber is part of the coupler.

 

[cookiemae]

Knuckle couplers, also known as janney couplers are the standard on U.S Railroads.
The inly real problem with them is that sometimes they break.
And yes, you can hear the slack from far away, and it is loud.
Take a look at this video...

http://www.youtube.com/watch?v=DmnN0qeMICE&feature=related

 

[Tokkyu40]

That was prtty cool!:Y:
It also led to a few clips of trains coupling up. Have a look.

American style Janney coupler.
http://www.youtube.com/watch?v=cxa7pLJTZpQ&NR=1
Good crew. So quiet you can here a pin drop. This, by the way, is supposed to be where that phrase came from.

British style screw couplers in Munich.
http://www.youtube.com/watch?v=CIUiyavOpO0&NR=1

And a modern MU coupler.
Since we don't want to neglect asia, here's a pair of E4 Max-Yamabiko trains in Sendai, Japan. (I rode one of these. Wonderful ride.)
http://www.youtube.com/watch?v=pKApUJ3VxIQ&feature=related

And uncoupling: http://www.youtube.com/watch?v=3qvsgtQQH5g&NR=1
This is the 400 series Tsubasa uncoupling from the E4 at Sendai for the Yamagata shinkansen. The E4 continues on the Tohoku line.

And no couplers, but interesting, a 400 on a transfer table...
http://www.youtube.com/watch?v=BtZjzmxDgag&feature=related

Claude

 

[JCitron]

Thanks for the awesome links, guys! Cool!

John

 

[big_b]

In the mines we used couplings very similar to those shown in the vid by cookiemae.We had to weld shrouds on top of them as they would slide apart due to the uneven track or use heavy safety chain between flattops if loading heavy mining machinery as they couldn't end load over a shroud tended to uncouple while being transported.

How often are the coupling checked for wear/damage? We had to check monthly with go/nogo gauges to check the tongue wear as well as ultra sound about every 6mths for cracks in the body/mounting pins.

Dave

 

[Evgeni01]

uk

In the UK knukle couplers are becoming more common especialy on block trains.

 

[springtransit]

Really? I notice the London Underground uses them, which is no surprise. Personally, I think the European countries should mandate the use of knuckle couplers for safety reasons, but that's just me.

 

[Tokkyu40]

Screw couplers are on the way out, but fully automatic multiple unit couplers are the best way to connect passenger cars.
Re: John Whelan's comment from Dec 16, Japan pulled all their rolling stock in to the yards in 1922 and switched completely from link and pin to Janney knuckle couplers in a single day. When they convert something, they don't play around.

Claude

 

[knil2gni]

Chain coupling, Screw coupling and Buckeye coupling.

All three methods were employed by British Railways over the millennium.
Chain coupling (Loose coupling) was employed on goods trains when a number of shunts into sidings formed part of the run. Also during that time there was a vast range of goods wagons being used unlike to-days container traffick.
Screw couplings were used on both Passenger and fast goods, perishables. Screw couplings took up the slack on the train and could travel at higher speeds.
Buckeye coupling, automatic coupling, used exclusively on Xpress Passenger and or mail.
Chain coupling, very often unbraked traffic.
Screw Coupling, two thirds braked traffic.
Buckeye coupling, fully braked traffic.