OK What Do These Silly Chains Do?

In the old days when you wanted to increase the tender's capacity you just gave one of the chains a good hard yank.

You're "yanking" my leg, right?

If not, I don't follow what you mean?

 

Rod

Good question. I've wondered that myself. 

Yeah. Yanking your chain. They run tender frame to truck so I've always thought they were a very slight crew safety device in the event of a derailment. Also they may have been used to move cars on adjacent tracks like a poleing rod would. I don't really have an answer.

They are indeed safety chains, or "anti-slewing" chains. If the locomotive derails, or worse yet, is involved in some sort of wreck, those chains keep the trucks connected to the tender frame. On steam locomotives, the engine truck (lead truck) also has those safety chains, and diesel locomotives still have them today.

Nope. Those truck safety chains are generally NOT removable in the field, plus they would be way too short for "chaining a car" that had had a complete coupler system failure (chain the car to a siding).

Safety chains on the tender trucks limit the rotation of the truck in the event of a derailment. 

I'm just looking for partial credit.

OK that's kind of what I figured.

so that is so as to lessen the severity in the event of a derailment of a tender truck I suppose?

I can certainly understand how they would help with the engine pilot truck.

 

Thanks for everyone's input.

 

Rod

Contrary to popular opinion, railroad cars, including steam locomotive tenders, just sit on their trucks. The trucks are not mechanically "connected" to the car. If you were to lift the car body of a steam locomotive tender with a crane, the trucks would stay on the rails. Of course, you would tear up the brake rigging and a few other things in the process, but the trucks would not lift with the car body.

 

Those chains keep the trucks close to the tender in the event of a serious derailment involving an upset or rollover, and they prevent the truck from slewing too far If they come off the rails in a minor derailment.

Yes, that's what we learned at the UP Cheyenne shops a few years ago.  Why?  To save maintenance time (therefore, $$$$) in changing out worn wheel-sets.

Didn't know that Rich. Thanks for the info!

Makes a lot of sense now.

 

Rod

They are on my Milwaukee Alco diesel also. Don

Well, in case of high winds they keep the tender body from blowing away.

 

Rick

OH YES! I forgot about that reason! 

 

Like this, for instance:

Some have said the "Wood Bros." came up with this idea long before they did the pit work for Colin Chapman and his Lotus team at Indy back in the sixties.

OK that makes more sense now.

 

Rod

There was an erie photo in Trains magazine of a line of trucks sitting on the tracks while the cars they had been under were lying on their sides adjacent to the tracks.  Hurricane Andrew had blown the cars right off the trucks while leaving the trucks undisturbed.

Hmm yes safety chains looks like they helped here...

 

 

 

 

 

While other wrecks you just have to say "How in the Heck did that happen"?

 

 

 

Seems I heard that line while out on a date many years ago....

Eerie photo:

Read more:  Altus Times - Strong winds blow over rail cars

 

 

 

I didn't know that Rich, but now the piles of trucks and wheels after a derailment makes perfect sense!

Not the picture I was thinking off but it makes the point

 

http://www.kfvs12.com/story/20...railment-in-scott-co

Here's a perfect example.

 

High winds blew these cars over and the trucks are scattered along the track...

 

Here's the nuts and bolts of why you want to try to keep the trucks of a derailed tender in line with the equipment:

 

Usually, derailments are minor in nature, and in line with the track -- typically, splitting a turnout or turning over a rail where tie conditions are poor such as yards, spurs, and sometimes sidings.  The best way to retail equipment is usually to use blocks and/or frogs to get the wheels back onto the rail.  Chains and a "come-along" are used to rotate the truck and guide it as the equipment is inched over the blocks.  With a typical freight car truck, it is much easier to rotate the truck than it would be with the typical six wheel tender truck.  Therefore, limiting rotation of tender trucks when they derail is more important and chains accomplished this.

 

In major derailments, as others have pointed out, it is important to keep the trucks from leaving locomotives if possible, and the chains also accomplished that.

Safety chains were required on passenger trains to prevent the trucks from going through the sides or floors of the passenger cars and crushing the passengers in roll over derailments.  They were replaced by locking center pins on more modern passenger cars.  I once did an economic analysis of frame keys which retain roller bearing wheel sets on freight trucks if they are derailed.  What I found was that a derailment of any particular car was so rare that no money could be justified to address derailment damage reduction devices.