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| A Switch in Time https://www.rypn.org/forums/viewtopic.php?f=1&t=37258 |
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| Author: | wesp [ Wed Oct 22, 2014 7:48 pm ] |
| Post subject: | A Switch in Time |
National Capital Trolley Museum has launched a Power2Give campaign to purchase a 22E Switch Stand with Transit Spring. A co sponsor will contribute 50 cents for every $1.00 donated to this project. http://power2give.org/MontgomeryCountyMD/Project/Detail?projectId=8644 Donors of at least $100 may schedule a time to operate a streetcar on the demonstration railway. Wesley |
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| Author: | Larry Lovejoy [ Wed Oct 22, 2014 10:41 pm ] |
| Post subject: | Re: A Switch in Time |
For those that might not know, a Model 22E switch stand is a "trailable" switch mechanism. If the points are set against you on a trailing movement, the weight of the rail vehicle will push them over. Unlike a spring switch, the points will then stay in that orientation until either the switch is thrown manually or the switch is trailed from the other track. The most important words above are "the weight of the rail vehicle". If the rail car is not heavy enough, the wheels won't be able to exert enough force against the open switch point to force it over, and a derailment will result. Thirty years ago, I was the trackwork design engineer on a light rail transit project that upgraded a pre-existing trolley line then operated with PCC cars. We needed some trailable switch stands and the Model 22E (at that time made by the now-defunct Abex Corporation) seemed like just the ticket. We installed a dozen of these puppies, mostly in the yard where speeds were slow, but several were temporarily installed out on the main line until the signal system contractor could get around to installing power switch machines. Late one evening, the motorman of "the bummer" (i.e. the last run for the night), having no passengers and in a hurry to get back to the car barn, attempted to trail one of these 22E equipped switches at about 25 mph. The virtually empty and hence very lightweight PCC car derailed in spectacular fashion. During the ensuing finger pointing, the folks at Abex told me: "Oh! You should have specified our lightweight spring cage assembly!" Naturally, no such option was called out in their catalog and their salesman, who had been pestering me for over two years at that point, never bothered to mention it, despite knowing exactly how we intended to use these switch stands. As I recall, Abex eventually furnished the lightweight spring retrofit kits free of charge. Fortunately, the folks at National Capital Trolley Museum are proposing to buy a Model 22E with a "transit spring", which apparently is the present day equivalent of the lightweight spring cage assembly. Anybody proposing to use a trailable switch under less than full railroad loading should consider the same. /s/ Larry Lawrence G. Lovejoy, P.E. |
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| Author: | Loco112 [ Thu Oct 23, 2014 1:13 am ] |
| Post subject: | Re: A Switch in Time |
Does anyone have a photo or two of the 22E? |
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| Author: | sbhunterca [ Thu Oct 23, 2014 8:02 am ] |
| Post subject: | Re: A Switch in Time |
Quote: Does anyone have a photo or two of the 22E? http://www.voestalpine.com/nortrak/en/products/Signaling/RACOR_Switch_Stands/Trailable-22E-22EH/ Steve Hunter |
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| Author: | PaulWWoodring [ Thu Oct 23, 2014 5:09 pm ] |
| Post subject: | Re: A Switch in Time |
So, if a railroad wanted to, it could make all of it's yard switches these things and never have to worry about "Run-Through" switch violations again, right? Would save a lot of investigation and out-of-service time, wouldn't it? |
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| Author: | Jim Vaitkunas [ Thu Oct 23, 2014 6:34 pm ] |
| Post subject: | Re: A Switch in Time |
Our Museum has a single point streetcar switch that has two settings. You can set it as a regular spring switch. If you want to make it act like a run-through you have to adjust a toggle in a flush metal box. We use it as a spring switch. Thanks! |
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| Author: | Alan Walker [ Thu Oct 23, 2014 6:47 pm ] |
| Post subject: | Re: A Switch in Time |
PaulWWoodring wrote: So, if a railroad wanted to, it could make all of it's yard switches these things and never have to worry about "Run-Through" switch violations again, right? Would save a lot of investigation and out-of-service time, wouldn't it? If it's a good design. TVRM got it's switches off of the Southern. One story was that the Southern had problems with the points not fully closing due to a design flaw. We got the switches, made a minor change and have never had any real problems. We do have one switch that has two settings. It is the No. 1 switch at East Chattanooga. Instructions require it to be operated manually, but as I recall, it could be trailed through without damaging the switch. Old Pueblo Trolley has four or five single point switches that can be trailed through and a couple of double point spring switches. As our trackage was removed during the Sun Link construction, all of the turnouts are stored. |
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| Author: | Bulby [ Thu Oct 23, 2014 9:01 pm ] |
| Post subject: | Re: A Switch in Time |
PaulWWoodring wrote: So, if a railroad wanted to, it could make all of it's yard switches these things and never have to worry about "Run-Through" switch violations again, right? Would save a lot of investigation and out-of-service time, wouldn't it? But where's the fun for the executives in removing the opportunity for rule violations? |
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| Author: | Dave [ Thu Oct 23, 2014 9:14 pm ] |
| Post subject: | Re: A Switch in Time |
I won't disclose the names and place, but I recall watching in horror than amusement as a two diesel lashup ran through a weighted lever throw switch with a bad latch.......the weight just jumped up to let each wheel through, then fell back down afterward. The hosteler running it got down to reline the switch only to find it already was lined the way he was going to line it......scratched his head, looked around, saw no damage and went about his business as usual. dave |
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| Author: | dinwitty [ Thu Oct 23, 2014 10:03 pm ] |
| Post subject: | Re: A Switch in Time |
hehe, thats any engineer's nightmare. I was josling my brain whudda this switch? then it got me, its throwing the points over. There must be a spring/latch mechanism to do this on the stand so it holds the points over sorta like an inverted V if you get my design drift. |
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