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| Wheel detectors (1169881) | |
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| (1169881) | |
Wheel detectors |
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Posted by Mr Railfan on Wed Aug 1 03:29:58 2012 I don't often post here , but i got a question, When a Train approaches a WD does the WD Blink first and then maintain a steady light or does it maintain a steady light (until the train is going the proper speed) and then blink?I recall that the WD entering nevins layup (IRT) maintains a steady light and then blinks , but at the same time i recall the Wheel detectors maintaing a steady light when switching between the express track and local track North of W4 st (IND). Anyway's any insight is appreciated! |
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| (1169887) | |
Re: Wheel detectors |
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Posted by G1Ravage on Wed Aug 1 05:42:52 2012, in response to Wheel detectors, posted by Mr Railfan on Wed Aug 1 03:29:58 2012. All lights are off if the Wheel Detector is not currently active.If active, the first light attached to the WD sign will be solid, which is a warning to the T/O that you're entering an active WD area. A bit further up will be a sign specifying the speed for the area, like "WD-20". The light beyond this sign, which was previously off, will start to flash as a warning that it's currently calculating your speed. If you're doing more than 20 MPH, it will continue flashing, and eventually trip your train. If you're maintaining 20 MPH or less, the flashing will soon turn solid, to let you know you're in the clear for now. |
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| (1169901) | |
Re: Wheel detectors |
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Posted by New Flyer #857 on Wed Aug 1 08:02:35 2012, in response to Re: Wheel detectors, posted by G1Ravage on Wed Aug 1 05:42:52 2012. What trips the train? A red signal that is connected to WD? The WD itself doesn't trip the train right? It tells a signal to clear? |
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| (1169902) | |
Re: Wheel detectors |
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Posted by Lou from Brooklyn on Wed Aug 1 08:06:48 2012, in response to Re: Wheel detectors, posted by New Flyer #857 on Wed Aug 1 08:02:35 2012. See section 3.3 of this document www.tsd.org/papers/APTA94.DOCThe two detectors are about 5 feet apart and have trips. |
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| (1169957) | |
Re: Wheel detectors |
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Posted by randyo on Wed Aug 1 16:39:37 2012, in response to Re: Wheel detectors, posted by G1Ravage on Wed Aug 1 05:42:52 2012. I never saws the exact situation you describe. From what I have observed, all wheel detectors flash until the approaching train slows to the required speed at which time it then illuminates steady. If the train should accelerate too fast, the WD light will again flash until the train is slowed to the required speed. Unlike conventional GT signals, the stop arm on a WD signal will come up under a train and trip it on other than the head car if the train should exceed the required speed after the lead car has passed the WD signal. |
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| (1169997) | |
Re: Wheel detectors |
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Posted by Broadway Lion on Wed Aug 1 21:50:48 2012, in response to Re: Wheel detectors, posted by randyo on Wed Aug 1 16:39:37 2012. LION understood:Dark = Signal not in use. LIGHTED = Signal controls speed: speed is within limits. FLASHING = Signals controls speed: You are too fast and will be tripped if you do not slow down now. LION has not seen signal flash in the non-presence of a train, and he has never seen it flash for a train that approaches slowly, in fact LION has never seen them flash. Good T/Os know their road and do not need to be bother with flashing WDs. ROAR |
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| (1170000) | |
Re: Wheel detectors |
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Posted by SelkirkTMO on Wed Aug 1 22:14:49 2012, in response to Re: Wheel detectors, posted by Broadway Lion on Wed Aug 1 21:50:48 2012. Probably because you can't get up to anywhere near tripping speed on the system anymore anyway. :) |
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| (1170032) | |
Re: Wheel detectors |
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Posted by G1Ravage on Thu Aug 2 05:00:48 2012, in response to Re: Wheel detectors, posted by randyo on Wed Aug 1 16:39:37 2012. Not all locations have an initial WD-warning light. |
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| (1170033) | |
Re: Wheel detectors |
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Posted by G1Ravage on Thu Aug 2 05:01:25 2012, in response to Re: Wheel detectors, posted by New Flyer #857 on Wed Aug 1 08:02:35 2012. There are trip arms with no signals randomly placed throughout wheel detector areas. |
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| (1170035) | |
Re: Wheel detectors |
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Posted by North-Easten T/O on Thu Aug 2 07:04:21 2012, in response to Re: Wheel detectors, posted by G1Ravage on Thu Aug 2 05:01:25 2012. OK G1 you can remain a T/O. You passed the test. |
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| (1170040) | |
Re: Wheel detectors |
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Posted by jrf2 on Thu Aug 2 08:15:47 2012, in response to Re: Wheel detectors, posted by G1Ravage on Thu Aug 2 05:01:25 2012. Something happened on the original post - if it suddenly shows up, please forgive the repost !!I am assuming that the speed is determined by the time between the frist and second axles on a car. I won't worry about the second axle on one car to the first axle on the next for now. In div B, there can be multiple classes of cars which will have different distances between the axles 1 - 75 foot cars 2 - 60 foot cars 3 - 54 foot cars (div A cars - yard moves, work trains etc. 4 - other equipment (desiels etc). How are their distances handled. A 54 foot car passes a point much faster (time wise) than a 75 footer which would cause a higher speed calculation. |
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| (1170053) | |
Re: Wheel detectors |
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Posted by Broadway Lion on Thu Aug 2 10:04:32 2012, in response to Re: Wheel detectors, posted by jrf2 on Thu Aug 2 08:15:47 2012. LION always assumed that an optical system was used and that it was not affected by such minutia. |
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| (1170057) | |
Re: Wheel detectors |
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Posted by Mr Railfan on Thu Aug 2 10:27:36 2012, in response to Re: Wheel detectors, posted by Broadway Lion on Wed Aug 1 21:50:48 2012. Here's a vid i took of a Flashing WD entering Nevins Layup:http://www.youtube.com/watch?v=gp6MuizAGH0 It looks as it was a solid white/not flashing and then began to flash as we approached it. |
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| (1170091) | |
Re: Wheel detectors |
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Posted by randyo on Thu Aug 2 14:54:16 2012, in response to Re: Wheel detectors, posted by jrf2 on Thu Aug 2 08:15:47 2012. No 54 ft cars, 51 ft! |
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| (1170111) | |
Re: Wheel detectors |
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Posted by Stephen Bauman on Thu Aug 2 15:58:44 2012, in response to Re: Wheel detectors, posted by jrf2 on Thu Aug 2 08:15:47 2012. I am assuming that the speed is determined by the time between the frist and second axles on a car.I'd assume they could at least detect the two trucks coupled between cars. They could also really be "wheel detectors" and detect the different wheels within a truck. There's a lot less variation in these distances than between the trucks in a single car. |
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| (1170115) | |
Re: Wheel detectors |
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Posted by Broadway Lion on Thu Aug 2 16:09:30 2012, in response to Re: Wheel detectors, posted by Stephen Bauman on Thu Aug 2 15:58:44 2012. LION assumes that it times the passage of a SINGLE WHEEL. A laser is aimed at the wheelsets, and the time of reflection back is what is being timed. Doesn't matter that there are 40 more wheels to pass. It times each one and if goes by too quickly the stop arms come up.ROAR |
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| (1170117) | |
Re: Wheel detectors |
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Posted by G1Ravage on Thu Aug 2 16:17:57 2012, in response to Re: Wheel detectors, posted by jrf2 on Thu Aug 2 08:15:47 2012. With certain work trains, Tower Operators are required to deactivate the Wheel Detectors prior to the work train arriving, to avoid such a situation. So yes, there have been miscalculations with work trains in the past. |
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| (1170138) | |
Re: Wheel detectors |
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Posted by Alex L. on Thu Aug 2 17:20:18 2012, in response to Re: Wheel detectors, posted by Broadway Lion on Wed Aug 1 21:50:48 2012. If you want to see a flashing WD, stand at the south end of the s/b plat at Brooklyn Bridge - watch the WD as a train goes into the loop. |
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