I’ve read about spring Switchs and I even saw a Photo of one on flicker, but I don’t understand exactly how it works or how is it activated. I know that movement through can’t not be reversed and that it returns to normal on its own after the train passes through, but what Throws it initially . Wikipedia has an animated diagram of a right-hand railroad switch (turnout) and they mention a spring Switch but no illustration. So does anybody know of such a drawing or animated diagram?
A model version of how they work, just imagine the spring on the prototype photo working like the axle on the model. http://www.youtube.com/watch?v=GHJBYoovloQ or the prototype http://www.youtube.com/watch?v=kxYLg5A5BuM&feature=related
A spring switch is vary simple. The switch is always lined for one direction of travel. This is considered the normal rout for this particular switch. The spring holds the points in this spot. For this example we will say it is in its normal spot is when the points are aliened for straight route threw. Trains can pass either way threw it without problems. A spring simply holds the points so that the rought is lined for the straight passage. When a train comes into the switch from the curved or diverging side of the switch, the points are still aligned to the straight rout, the wheels of the on coming train force the points to slide over as they pass threw the switch. When each wheel set pass completely over the points and clears them the spring will pull the points back to the other side ( putting it back in the normal route ). This means as each car pass over, the first truck forces the points over, then when the first truck clears the points they snap back until the next truck of the same car forces the points back over as they pass over. If your train stops and a car has one truck one each side of the points, an we where going into the switch from the curved side ( as in our example), the lead truck is just passed and clear the points, the points reline to the straight path, and the second truck of the car has not yet started on the points. As long as the train continues to move in the same direction this work just fine, but if you stop over the switch at this point and back up the train, the first truck will back down the straight part of the switch and the second truck will remain on the curved part of the switch. Now in our example we used a switch that the spring was set so that normal rout was always straight, you cal also set a spring switch to use normal rout as diverging or curved, it has to be one or the other. The wheels of the passing car force the points over and the spring brings the points back to normal.
Check this out you see the points snap back real good. http://www.youtube.com/watch?v=oWIB2iF6ld4&feature=related I found this after i watched the other url posted by Geared Steam, they where cool and as always once on Youtube, I just cant stop clicking!
Ok now I understand. Well heck that’s how my atlas turnouts work now. laugh: I was confused, because I was watching a UP video on YouTube video that had a train waiting on a center siding with a main on each side and they mentioned that the siding could be entered from either main, but now I see that it is only in one direction. The switch looked more like a wye and I didn’t understand how the waiting train got unto the siding in the first place. This is the video where I first learned of the spring switch. It is mentioned at about 3:56 min into it, http://www.youtube.com/watch?v=xO2y2YFpk2c Anyway thanks a lot guys those where great videos :thumbs_up:
The transit system I worked for had one spring switch which lead into a tail track where the car washing system was located. It was protected by dwarf signals for both directions. When a train was being washed there would be a motorman on both ends of the train. One MM would pull the train through the switch past the signal and the other MM would pull the train back through the car wash. Several times over the years a train would not completly clear the switch and the motorman would not look for the signal and pull the train back stradleing the two tracks,and demolish the car wash walls and derail. The switch was an interesting device. All the other switches in the yard were controlled by the tower with powered machines. This spring switch was a hand throw that had contacts inside for the signals, with a large hydrolic spring cylinder between the points which was connected to the throw bar. As the train approached the switch it would pass over the frog. The next section of rail before getting to the points had a tighter gauge to it (less than 56-1/2 inches) and was floating (not spiked down but it could only move sideways a little). There was a rod connected to it and a bell crank off to the side of the track. Another rod went from the bell crank to the hand throw. As the train pushed this rail sideways it would turn the bell crank and pull the other rod outward from the handthrow to unlock the points. The wheels would then push the points over. When the train cleared the switch the hydrolic cylinder would push the points back and the rod would go back and lock the points and clear the reverse signal. There were no spare parts for this switch. If something broke we would have to make it or get the machine shop to fabricate a new part. The company wouldn't buy any spare parts from GRS. Many years ago I used an Atlas switch with the side mounted machine as a spring switch on a loco escape track. It worked for loco's only as the cars were too light to push the points over.
I think I understand it now after I watched the UP video again and after I posted last. I finally heard it mentioned that a crew member manually throws a switch to enter the siding from either main and it’s automatic only when exiting the siding. The center switch in the siding is a wye so it not completely automatic. I’m assuming that the center spring switch is nominally open to the main on the side and springs open to trains entering the siding on the other side. The main spring switches would have to be spring held in the straight through position for the main. So in order for this particular center siding to work it would have to have 6 spring switches.
The old Boston and Maine had 2 spring switches in the engine terminal area at Woodsville, NH. There were two turntable leads coming from opposite directions. Each of these tracks had a spring switch that served the through ash pit track. While the hostlers/engine crews had to manually line a switch to access the ash pit, they didn't need to do that in order to exit the track. Naturally, the turntable routes were the normal positions as they were used more frequently. Duane Goodman
No, four, as I think it says in the video. Taking one end (either) and assuming right hand running: If you are (say) Westbound then as you approach the siding the facing switch on 'your' track will be a manual one. The trailing switch on the other, Eastbound, main will be sprung to the straight through (main) route. The siding switch will be sprung to direct Eastbound trains onto the Eastbound main; obviously any other arrangement would be highly dangerous. If your train is holding the WB main it goes straight on at the switch and then through the trailing sprung switch at the other end. If you are taking the siding a crew member lines the manual switch for the siding. Your train is then diverted left and trails through the centre spring switch, pushing the blades over, to enter the siding. When leaving at the far end the centre spring switch there directs you right towards the Westbound main and you then trail through the WB main spring switch, pushing the blades over, to enter the WB main again. So that's one manual and two spring switches at each end, 2 man + 4 spr total.
So in other words, on the attached diagram, the points circled in blue are sprung, and aligned by default to allow the train on the siding to re-enter the track that he left, but not to enter the other main. Right? That way running the wrong way requires a deliberate act - the brakeman/conductor stepping down and manually throwing the points the other direction... on TWO switches (the exit wye and the entrance turnout for the opposing track).
I don't think a spring switch would be used in a situation you have shown. Since the conductor or brakeman would have to climb down to throw the entering switch anyway. It's more for a passing track with the switch at one end lined for the passing track and the switch at the other end lined for the main so a train coming from either direction would not have to stop to throw a switch, entering or leaving. It works good for a train without a crew in a caboose.
That"s a great example, good find.:thumbs_up: I know what you mean about youtube, sometimes I have to force myself to x out!
I have learned so much from YouTube. Unfortunately I didn't think to look there this time around. You just need to know what you’re looking for. I even learned how to make my own Printed circuit boards from YouTube and built 8 boards in my garage. There is just an endless amount of free information on the internet. :tb-biggrin:
