Why are these springs necessary

Discuss park gauge trains and large scale miniature railways having track gauges from 8" to 24" gauge and designed at scales of 2" to the foot or greater - whether modeled for personal use, or purpose built for amusement park operation or private railroading.

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Re: Why are these springs necessary

Post by LVRR2095 »

Geochurchi wrote: Thu Mar 17, 2022 7:12 am
Bill Shields wrote: Wed Mar 16, 2022 8:14 am less parts all seems like a good idea until someone runs through the closed switch and derails and entire train full of cars and or damages the switch because something is now bent

the, all of a sudden -> that $4 spring seems like a good idea.
It seems to me that the real reason for the springs is to prevent a derailment if a train is going into a turnout in the wrong direction , do real railroads have these devices?
Yes,,,real railroads use spring switches. In fact the Seashore Trolley Museum here in Maine have them on the main line so they can run without having to stop and throw switches with oared passenger cars.
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Re: Why are these springs necessary

Post by Jacob's dad »

Pontiacguy1 wrote: Tue Mar 15, 2022 3:04 pm When you build a switch with the springs in it to move the points, I.E. a Sprung switch, you need to be careful about how stiff you make your springs. if they are too stiff, then lighter cars will end up derailing instead of moving the points over and running through the switch. If they are too light, then the switch will tend to not move all the way over into the proper position when you throw it, especially if it has a lack of lubrication or a little bit of dirt or tree sap or whatever in it that might make it want to stick.
So what should the spring rate be, please? Would McMaster Carr part #1986K609 be an acceptable spring for 7-1/2" gauge?

Thank you,

Jeff Smith
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Re: Why are these springs necessary

Post by NP317 »

"...with oared passenger cars."

Makes me picture a Roman Galley... 😱😂
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Re: Why are these springs necessary

Post by PeterCraymer »

Strasburg has spring switches in multiple locations along the line and see many operations everyday.
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Re: Why are these springs necessary

Post by Gra2472 »

Oared passenger cars are for those really steep grades.
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The railroad is almost done.
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Re: Why are these springs necessary

Post by Bill Shields »

Spring rates are a function of the switch mechanism and minimum weight on an axle.

Irrespective of what anyone suggests, you are going to have to $ few springs, install the appropriate mechanism on a turnout, find the LIGHTEST car at the track....and play with it.

After you have done a few, you will have a pretty good idea of what is needed.

As a starter, you can push a lightweight car into an existing switch while you pull with a spring scale until the wheel rides up and over instead of through....and still puts the points back in place after the car has passed.

Rough...but a starting point.

A small 'bobber' caboose would be a place to look at for lightest wheel load.

It is not rocket science, and the effort to learn very rewarding.
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Re: Why are these springs necessary

Post by ccvstmr »


There's no good way to determine the spring rate in advance. It's something you "get a feeling for" by moving the points during turnout assembly. When setting the spring stops/collars...push the point over maybe 6 to 8" back from the tip of the points. You're trying to simulate a wheel trailing thru the switch and pushing the points to the side as the train passes. Springs need to be set so train wheels can easily push the points out of the way, but still spring back and nest against the stock rail.

Will add...I don't recommend "oiling" the ties so the switch points can move. Oil only attracts ballast, grit, grim, dust and other to gum up the works. Instead, if you haven't done so already, consider putting stainless steel slide plates under the switch points. Can even cut up stainless steel banding for this. After installation, let Mother Nature clean the shims when it rains!

32 slid shims under points.JPG
32 slid shims under points.JPG (125.4 KiB) Viewed 713 times

Spring adjustments were done to the side for easy access by moving a spring stop collar. Use of ferrous materials was minimized to maintain smooth operation of the points and switch throw mechanism. The white nylon block(s) were eventually replaced with black nylon to avoid UV degradation.

35 switch throw detail.JPG
35 switch throw detail.JPG (136.46 KiB) Viewed 713 times

Can also bend the switches with a slight "crown" so when unloaded, the point only contacts the ties/shims near the point ends. When a train passes, there's usually enough weight there to push the point down so it contacts the slide shim. Make sense? Good luck. Carl B.
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Re: Why are these springs necessary

Post by Odyknuck »

The springs we use at the club are not very strong as you can easily move the points by hand.
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