I have several spring switches in use, so a bit of explanation may be in order:
First, what is a spring switch? It's either a normal switch where the points are held against the stock rail by a soft spring (or the spring action of the rail) but can be forced open by wheels moving through trailing point from the less-favored branch, or a purpose-designed single point switch (like a streetcar switch) with a clearance device replacing the second point. The latter are seriously ugly, but more reliable in operation.
Spring switches always route a facing-point movement to the more favored branch, so the less-favored branch is effectively one way, trailing point only.
Having the points spring-loaded one way does NOT change the requirement that rail polarity must be set up so that a locomotive passing through from the less-favored branch will not cause a short. This means that a solid-frog turnout will have to have the frog polarity switched even though there is no switch machine to move the points.
One BIG disadvantage of a spring switch will show up if a train moving from the less-favored branch is ever backed up before the last car clears the switch. The worst case would end up with one car trying (unsuccessfully) to go both ways. Don't ask how I learned this!
Spring switches are useful for special applications, but are not intended to permit inattention on the part of the operator.
Chuck (Modeling Central Japan in September, 1964 - with spring switches)
That explanation went so far over my head I didn't even see it.
Thank you though!
In 1:1 scale, sprung frogs have been around for a long time. I have a Pere Marquette MOW drawing booklet from the 40's with a drawing of a sprung frog. These were truly sprung. No extra switch motors were used. These were used so that the flangeway for the lesser used diverging route was closed and thus there was less wear on the track and on the wheels, not to allow a train to pass though a turnout that was set for the wrong direction.
The weight of real freight cars and locomotives passing through the frog was all that was necessary to move the frog. Unfortunately, our model rolling stock is much lighter. An operational sprung frog in HO scale would be very touchy and challenging to make reliable.
I've recently seen an advertisement marketing a device that will realign a turnout if the train approaches from the "wrong" track. I forget where, but it I think it was a DCC-related product hooked up to the electric switch machine.
Mark
I have never heard of an HO scale turnout with a spring in the frog as you describe. Movable frogs are just beginning to be used on some mainline railroads because they are a fairly recent development.
A photo of one I saw being installed by the Union Pacific said it required two switch motors wired so they moved in synchronization -- one for the points and one for the frog; and that they are so complicated and expensive they are being installed only in areas requiring crossovers on high speed mainlines.
If your layout is DCC, Tony's Train Exchange sells an electronics device that can detect an improperly set turnout and throw the switch if a model train is going through from the wrong direction, but this has nothing to do with the turnout frog.
Thanks for the answer.
I thought there were HO scale turnouts that had sprung frogs where if you back a car onto a switch that was turned, the spring would allow the frog to move and prevent derailments.
Checking my source will be my next move.
Thanks again.
There are two types of spring loaded turnouts. As already mentioned, Peco is one with a spring to hold the points in position. This spring is quite strong and will not be overcome by the train going through the turnout if it is set in the wrong direction.
The second type is a turnout where you install a rather weak coil spring to hold it in one position on a turnaround loop. As a train enters the loop, the spring holds the points into position, and as the train exits the loop the wheels can push the points open against the spring enough to pass through, so no switch motor or ground throw is necessary. With this, the train always goes around the loop in the same direction. This type of spring arrangement can also be used on a siding where a train will always be running in the same direction off of the siding onto the main line.
The sprung turnouts you must be referring to are Pecos. No they will not help if set wrong. The spring is an over center spring to keep the point rails tight against the stock rail. This is so no other motor or ground throw is needed.
Pete
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Hello friends.
I am hearing of these spring loaded turnouts.
I have derailed trains because of having my turnout switches in the wrong position.
Are these spring loaded turnouts good to use or shall I stick to the manual ones.
Any of your opinions are appreciated.
Thanks,
jkoso