Spring Switches

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Spring Switches
Posted by Northtowne on Sunday, April 1, 2012 7:18 PM

I would like to know a little more about spring switches. I assume that most sidings (that are so equipped) would have them at both ends. To enter you would have to manually open them, right?. Would the trainman have to wait to line them back? Do they show their alignment the same as other switches? This has probably been discussed here many times but I haven't caught it, so I am asking you all.

Northtowne

 

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Posted by mudchicken on Sunday, April 1, 2012 7:35 PM

What trainmen call spring switches (which aren't) or the real thing ?

(1) Mechanical switchman in the switch rod assembly (coil spring in a tube housing/ aka shock absorber)

(2) spring frog (weight of the wheel opens the flangeway held shut by the horn spring)

(3) Swing nosed frog

(4) variable switch stand

1, 2 & 4 can be run through in the trailing motion

To approach in a facing point move, you have to manually open the switch. 

They can be equipped with switch targets showing their alignment.

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Posted by Deggesty on Sunday, April 1, 2012 7:40 PM

Northtowne

I would like to know a little more about spring switches. I assume that most sidings (that are so equipped) would have them at both ends. To enter you would have to manually open them, right?. Would the trainman have to wait to line them back? Do they show their alignment the same as other switches? This has probably been discussed here many times but I haven't caught it, so I am asking you all.

Northtowne

 

Since the points would spring back to the default position in a trailing move, it is not necessary to line the switch back.. In all probablity, the location of spring switches would be noted in the Employee Timetable, and there would be a sign (at the points?) showing "SS." I am not certain, but the target/light on the switchstand I believe would indicate only the position determined by how the switch was thrown manually or by remote control. not by how the points are moved by a trailing movement.

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Posted by Deggesty on Sunday, April 1, 2012 7:43 PM

If you enter a track (facing points move) that has a spring switch, the switch must be lined for that track and then lined back, since the spring works only on trailing moves.

Johnny

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Posted by K. P. Harrier on Sunday, April 1, 2012 9:40 PM

Hi Northtowne!

In the last 30 years spring switches have increasingly fell to the wayside.  This is because of the increasing popularity of Centralized Traffic Control (CTC) that maximized track efficiency and return on investment without great expense.

Spring switches of yesterday were most popular on double-track (NOT two-track) lines, where each of the tracks were Automatic Block Signaled (ABS) in only one direction, and each track had a current of travel.  To get out of the way of a faster train, a train would stop, thrown the switch, and enter the siding.  The caboose crew would normalize the entrance switch when they were off the mainline.  Once the faster train passed, the head end crew would just head out onto the mainline without having to throw the switch (the weight of the locomotive moved the points), nor would the train have to stop so the caboose trainmen could throw the switch back, because the points would just automatically 'spring' back to normal with the last car's passing, hence, the term spring switch.

Old time railfans grew up with double-track ABS, so knew the term well.  Today's upcoming crop of railfans hardly experience one train passing another in ABS territories, hence, it is not surprising this thread's question surfaced.

Take care,

K.P.

----------------------------------------------------------------------------------------------------------------------------------- K.P.’s absolute “theorem” from early, early childhood that he has seen over and over and over again: Those that CAUSE a problem in the first place will act the most violently if questioned or exposed.

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Posted by Georgia Railroader on Sunday, April 1, 2012 11:16 PM

I see them everyday, they are the best thing to have in dark territory as it speeds things up from not having to walk the train. The spring switch will have an indicator light either green or red to let you know the position of the switch. A few miles before getting to that switch will be a non automatic block signal which will tell you in advance what the position of that switch will be. You get either a clear or an approach. Spring switches can hang up, they can also get debris in the points which will cause the switch to not line back to the main. This is why we have the signals ahead of time to let us know so we dont round a curve and find a red switch marker light and a switch that did not spring back. Bad news at 49mph.

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Posted by daveklepper on Monday, April 2, 2012 5:05 AM

Spring switches were the standard practice for classic single-track streetcar lines.   Both ends of the short stretch of double track that would constitute in railroad terms a main line and siding would have spring switches, usually insalled so a streetcar entering at either end always takes the right-hand track.  Typical applications included the Counsel Crest line in Portland, OR, the Warburton Avenue, Neperhan Avenue, and Tuckahoe Road lines in Yonker, NY, the Charleroi and Washington (PA) innteruburban lines of Pittsburgh Railways, the entire West Penn system, and many, many more.    Also, on double track lines using double-end streetcars, there would be trailing crossovers, with both switches spring switches.   A "short-turn" streetcar could thus simply end its run short of the end of the line, by reversing and allowing the spring switch to cross it over to the opposite track for the return move.  In Manhattan, the Broadway - 42nd Street line (1st Avebue and 42nd Street to 129th Street and Asterdam Avenue) had short-turn trailing crossovers at 3rd Avenue, 5th Avenue, 57th Street, one on the 10th Avenue tracks at 72nd Street used by cars from the north reversing, and 106th or 107th Street. 

 

Of course, for some emergency purpose, it was always possible to defeat the spring action.

 

Most streetcar switches were constructed with only one movable point, the :ouside rail of the curve.  Where the inside-curve point would be located, there was simply a flangeway that divided to tow paths.

 

In Jerualem light rail, all switches are powered, controlled from a central locaton, and all have two points.

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Posted by CSSHEGEWISCH on Monday, April 2, 2012 7:01 AM

The South Shore Line is single-track east of Gary and most of its passing sidings (generally around a mile long) are equipped with spring switches at each end.  This set-up made meets both scheduled and unscheduled a lot easier to arrange and was sometimes described as a "poor man's CTC".

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by daveklepper on Monday, April 2, 2012 7:23 AM

Ah!  One bit of interurban heratage lives on on the South Shore!     Typical interurban line practice.

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Posted by SFbrkmn on Monday, April 2, 2012 4:48 PM

This is somewhat of a rare use for a Spring switch that centers at Garden City, KS. Yrs ago the siding in town was about 12000ft w/ Spring switches at both ends.Later a crossover was installed about 1/3rd of the way east of the west switch. The trk to the east of the XO was the 'siding" while the trk to the west was changed to a storage yd trk. However, the west spring switch was never taken out and still remains in use to this day. So basically you have a yard trk protected by a spring switch. Not a  very efficient when switching and having to line such a device several times back & forth. Also a good way to define how a spring switch works to someone who may not understand how it works can be made simple comparing such a switch to a screendoor w/ a spring on it: open the door manually and the screen on the door will allow it to close on its own.

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Spring Switches
Posted by blue streak 1 on Monday, April 2, 2012 7:27 PM

didn't NS install spring switches on the line west out of Mannasas, Va ?? that was a dark line ?

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Posted by daveklepper on Tuesday, April 3, 2012 6:30 AM

The reason spring switches were more prevelant on interurban and streetcar lines than on major freight railroads was the matter of wear and tear.   When a train moves through a trailing spring switch set against its route for the oncoming traffic, the points move back and forth with the passage of each axle!   With a single streetcar or interurban car, that is four times, but for a 100 car freight train with say a good 2-8-2 steam locomotive pulling, that is 406 times, or 410 times with a caboose.

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Posted by Readingfan2124 on Tuesday, April 3, 2012 5:43 PM

Strasburg uses spring switches on their sidings to minimize crews having to throw switches at each end where the engine runs around the train and at the grove siding mid-way where two trains meet, when they run two trains.

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Posted by cx500 on Tuesday, April 3, 2012 8:34 PM

There are several situations where I have seen them.  One is at the end of double track in ABS territory so trains going onto single track could continue through without stopping.  Another is in CTC, where a siding has a power switch at one end and a spring switch at the other, thus saving the cost of a switch machine and its controls.  When setting up meets the dispatcher  was forced to put trains into the siding based on direction, not priority.  Since the switch returns to normal after the train has passed through there is no need for the train to stop or a crew member reline it.  But if for some reason the train stops and has to reverse, the switch has to be manually lined FIRST.  I have also seen a crossover with a power switch at one end and a spring switch at the other.  A balloon track is another situation where a spring switch can be effective.

On a main track I think it safe to say the switch will always be protected by signals.  An oncoming train approaching the facing points needs to know positively that the points have returned fully to the normal position.  A switch hung up part way over is a certain recipe for derailment.  Even a reversed switch may result in a derailment if the train is travelling too fast.

John

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Posted by Paul_D_North_Jr on Tuesday, April 3, 2012 8:58 PM

daveklepper
 The reason spring switches were more prevelant on interurban and streetcar lines than on major freight railroads was the matter of wear and tear.   When a train moves through a trailing spring switch set against its route for the oncoming traffic, the points move back and forth with the passage of each axle!   With a single streetcar or interurban car, that is four times, but for a 100 car freight train with say a good 2-8-2 steam locomotive pulling, that is 406 times, or 410 times with a caboose. 

Good point.  To counteract that, some spring switches (and spring frogs) are/ were equipped with hydraulic dampers/ 'dashpots' / shock absorber-like devices which slow and delay the spring-driven return of the switch (or frog wing rail, etc.) for several seconds.  By then, the next wheel/ axle is usually passing through, so there's much less cycling back-and-forth until the last axle of the last car clears the switch, minimizing that wear-and-tear.  

- Paul North.   

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Posted by BaltACD on Wednesday, April 4, 2012 6:40 AM

While not a Spring Switch - back in the 70's there was a lot of advertising for Racor Switches.  The Racor switch could be trailed through and line the route that you could then shove back through without having broken the switch lug as happens with a standard hand operated switch.   With previously run-through switches being a leading cause of yard derailments, this just seems to be too simple of a fix.

I haven't seen or heard much about them in the present world.

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Posted by ronsal on Wednesday, April 4, 2012 7:43 AM

Does anybody have a picture of one of these?  I am wondering if they look any different.

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Posted by mudchicken on Wednesday, April 4, 2012 8:24 AM

Sounds like a 22-P/ 22-E variable switch stand (not a spring switch).....thousands of them out here in yards (never on a main track), often called a "barrel switch" by trainmen, it has a large coil spring under the barrel housing....competitor for the CTM/Pettibone Hub Safety Switch and the much older Racor/Ramapo Ajax box stand variable switch. All use some type of spring to cushion the points and rods when lined over under the weight of (force of) the railcar wheels pasing over the switch points.

Nortrak/RACOR and CTM/Pettibone are still cranking them out. The old box stands are museum pieces, haven't been made for years.

 

 

Mudchicken Nothing is worth taking the risk of losing a life over. Come home tonight in the same condition that you left home this morning in. Safety begins with ME.... cinscocom-west
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Posted by zugmann on Wednesday, April 4, 2012 8:33 AM

BaltACD

While not a Spring Switch - back in the 70's there was a lot of advertising for Racor Switches.  The Racor switch could be trailed through and line the route that you could then shove back through without having broken the switch lug as happens with a standard hand operated switch.   With previously run-through switches being a leading cause of yard derailments, this just seems to be too simple of a fix.

I haven't seen or heard much about them in the present world.

I always heard they "cost too much to maintain".  Yet calling hulchers out and shutting down part of the yard for a day, fixing equipment,and having trials always seemed expensive to me.  Guess I don't see the "big picture".

 

I worked at a small yard for a mill that had switches you could run through.  I heard some of the hoggers would play a joke on new conductors that didn't know about those kind of switches.  They'd go down the ladder plowing through all the switches  as the brand new conductor is convincing himself that he is now fired.  

 

 

 The opinions expressed here represent my own and not those of my employer or any other railroad, company, or person.

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Posted by BroadwayLion on Wednesday, April 4, 2012 10:09 AM

Out here BNSF has a fancy switch on the mane lion that the conductor called a "poor man's interlocking".

When taking the siding, he would climb down ahead of the locomotive, and would align the switch with a pumping action. He would climb back up onto the locomotive and when the entire train had cleared the switch it would snap back to the main line. I do not know the electronics or the mechanics involved, but these appeared when the caboose disappeared.

ROAR

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Posted by mudchicken on Wednesday, April 4, 2012 10:12 AM

BroadwayLion

Out here BNSF has a fancy switch on the mane lion that the conductor called a "poor man's interlocking".

When taking the siding, he would climb down ahead of the locomotive, and would align the switch with a pumping action. He would climb back up onto the locomotive and when the entire train had cleared the switch it would snap back to the main line. I do not know the electronics or the mechanics involved, but these appeared when the caboose disappeared.

ROAR

Old style hydraulic switch stand w/o electric assist. Dangerous things.

Mudchicken Nothing is worth taking the risk of losing a life over. Come home tonight in the same condition that you left home this morning in. Safety begins with ME.... cinscocom-west
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Posted by Victrola1 on Wednesday, April 4, 2012 2:18 PM

Probable Cause

The National Transportation Safety Board determines that the probable cause of the September 15, 2002, derailment of Norfolk Southern train 15T was (1) the decision by the train dispatcher and signal maintainer to allow the train to pass over the spring switch at maximum authorized speed before the switch had been adequately inspected or clamped closed and (2) the lack of company procedures requiring that train dispatchers, after receiving a report of a problem involving a main track switch, immediately stop trains or implement an appropriate speed restriction in the affected area.

http://www.ntsb.gov/investigations/fulltext/RAB0305.html

How much of a maintenance problem are spring switches?

 

 

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Posted by BaltACD on Wednesday, April 4, 2012 2:51 PM

Victrola1

Probable Cause

The National Transportation Safety Board determines that the probable cause of the September 15, 2002, derailment of Norfolk Southern train 15T was (1) the decision by the train dispatcher and signal maintainer to allow the train to pass over the spring switch at maximum authorized speed before the switch had been adequately inspected or clamped closed and (2) the lack of company procedures requiring that train dispatchers, after receiving a report of a problem involving a main track switch, immediately stop trains or implement an appropriate speed restriction in the affected area.

http://www.ntsb.gov/investigations/fulltext/RAB0305.html

How much of a maintenance problem are spring switches?

 

 

Any part the moves is a maintenance problem - to keep it moving properly and to make sure it's alignment is proper with the parts it moves in relation to.  If MofW had their druthers, all switches and special track work would be done away with, because they are all maintenance hassles and money pits.

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Posted by BroadwayLion on Wednesday, April 4, 2012 2:56 PM

mudchicken

 

 BroadwayLion:

 

Out here BNSF has a fancy switch on the mane lion that the conductor called a "poor man's interlocking".

When taking the siding, he would climb down ahead of the locomotive, and would align the switch with a pumping action. He would climb back up onto the locomotive and when the entire train had cleared the switch it would snap back to the main line. I do not know the electronics or the mechanics involved, but these appeared when the caboose disappeared.

ROAR

 

Old style hydraulic switch stand w/o electric assist. Dangerous things.

 

 

It *CAN'T* be "old-style".... I watched them install that thin just 20 years aog.

ROAR

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Posted by BaltACD on Wednesday, April 4, 2012 3:38 PM

BroadwayLion

 mudchicken:

 

 BroadwayLion:

 

Out here BNSF has a fancy switch on the mane lion that the conductor called a "poor man's interlocking".

When taking the siding, he would climb down ahead of the locomotive, and would align the switch with a pumping action. He would climb back up onto the locomotive and when the entire train had cleared the switch it would snap back to the main line. I do not know the electronics or the mechanics involved, but these appeared when the caboose disappeared.

ROAR

 

Old style hydraulic switch stand w/o electric assist. Dangerous things.

 

 

 

It *CAN'T* be "old-style".... I watched them install that thin just 20 years aog.

ROAR

Railroads are doing trackwork upgrades faster than they were 20 years ago!

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Posted by mudchicken on Wednesday, April 4, 2012 7:23 PM

Correct on moving parts (points or spring frog) being a problem.

The spring part wasn't a problem here, the rod and the points were well out of adjustment ..... all it took was one wheel, less than round on the edges and it all goes to heck.. I would have expected the switch point to be obviously smashed in the photo. The point should always be tight against the stock rail - NO gapping at all.

Spring frogs fell out of favor in the 1970's because of the adjustment of the horn spring that closed the flangeway on the frog, especially when the rail ran (expanded in the heat and the anchors could not hold the rail in place (FRA Exceptions Deluxe). The technology has improved and spring frogs are coming back into vogue.

Mudchicken Nothing is worth taking the risk of losing a life over. Come home tonight in the same condition that you left home this morning in. Safety begins with ME.... cinscocom-west
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Posted by Falcon48 on Thursday, April 5, 2012 10:31 PM

A big problem with spring switches (either with springs or "dashpots") is their accident potential. If a train reverses movement after partially springing though a switch, the train will split the switch.  This wasn't so much of a problem with the short trains on interurbans, but it's a much more serious potential with longer trains, particularly at locations where switching is performed.  Illinois Railway Museum had an expensive spring switch accident with their Nebraska Zephyr trainset a few years ago(since repaired) involving this scenario.

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Posted by BaltACD on Friday, April 6, 2012 6:35 AM

Falcon48

A big problem with spring switches (either with springs or "dashpots") is their accident potential. If a train reverses movement after partially springing though a switch, the train will split the switch.  This wasn't so much of a problem with the short trains on interurbans, but it's a much more serious potential with longer trains, particularly at locations where switching is performed.  Illinois Railway Museum had an expensive spring switch accident with their Nebraska Zephyr trainset a few years ago(since repaired) involving this scenario.

Human Failure - pure & simple.

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Posted by Falcon48 on Friday, April 6, 2012 4:20 PM

BaltACD

 Falcon48:

A big problem with spring switches (either with springs or "dashpots") is their accident potential. If a train reverses movement after partially springing though a switch, the train will split the switch.  This wasn't so much of a problem with the short trains on interurbans, but it's a much more serious potential with longer trains, particularly at locations where switching is performed.  Illinois Railway Museum had an expensive spring switch accident with their Nebraska Zephyr trainset a few years ago(since repaired) involving this scenario.

 

Human Failure - pure & simple.

  Very definitely human failure.  It's just that a spring switch creates more opportunity for this kind of failure, particularly if it is in an area where trains might be expected to reverse movement over the switch.  Regular switches have to be aligned for a trailing movement, so the train won't split the switch if it reverses before entirely clearing the switch.  A spring switch, on the other hand, doesn't have to be aligned for a  trailing movement, since the train wil simply spring throught the points.  This creates the potential that the crew will forget which way the switch was set (or won't check it) before reversing movement.  Just one more thing to go wrong.  A solution to this issue that many railroads employ in yards is a switch where the points push aside for a trailing movement, like a spring switch, but then stay in the new position, rather than returning to the original position.

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Posted by BaltACD on Friday, April 6, 2012 6:48 PM

Falcon48

 BaltACD:

 Falcon48:

A big problem with spring switches (either with springs or "dashpots") is their accident potential. If a train reverses movement after partially springing though a switch, the train will split the switch.  This wasn't so much of a problem with the short trains on interurbans, but it's a much more serious potential with longer trains, particularly at locations where switching is performed.  Illinois Railway Museum had an expensive spring switch accident with their Nebraska Zephyr trainset a few years ago(since repaired) involving this scenario.

 

Human Failure - pure & simple.

 

  Very definitely human failure.  It's just that a spring switch creates more opportunity for this kind of failure, particularly if it is in an area where trains might be expected to reverse movement over the switch.  Regular switches have to be aligned for a trailing movement, so the train won't split the switch if it reverses before entirely clearing the switch.  A spring switch, on the other hand, doesn't have to be aligned for a  trailing movement, since the train wil simply spring throught the points.  This creates the potential that the crew will forget which way the switch was set (or won't check it) before reversing movement.  Just one more thing to go wrong.  A solution to this issue that many railroads employ in yards is a switch where the points push aside for a trailing movement, like a spring switch, but then stay in the new position, rather than returning to the original position.

Switches - any kind - are man failures accidents waiting to happen.  Any kind of error in the operation of a switch - regular hand throw - Spring Switch - Racor Switch - Power Switch - WILL happen at some point in time.  All switches have rules that govern their proper operation - it is human to break rules, either inadvertently or intentionally - generally with 'accidental' results and the need to rerail some equipment.

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