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| Manually changing points in anticipation of setting route 28/08/2013 at 17:22 #48950 | |
postal
5265 posts |
" said:Aha....as I thought so Sorabain plan to manually key points will backfire at some point (no pun intended!).....But I can see what Sorabain wants to do, and I've done the same on Stafford (particularly when I'm running with the Gremlins). If you manually set the points early and they fail, you have a sporting chance of diverting a train round the failure and you also start the countdown to the fault being fixed a little earlier. I know the counter argument that if you waited to set the points at due time then they might not fail but it is a case of setting things early in the hope that it is easier to work round any problem rather than waiting for due time then having a problem in your face. “In life, there is always someone out there, who won’t like you, for whatever reason, don’t let the insecurities in their lives affect yours.” – Rashida Rowe Log in to reply |
| Manually changing points in anticipation of setting route 28/08/2013 at 17:24 #48951 | |
Danny252
1461 posts |
" said:But who is to say that the points won't fail when you move them manually, in which case you are still in the same boat!!His point was more that if you key them and they break 20 minutes before the next train is due, that's either 20 minutes to do something about rerouting said train, or 20 minutes less everyone has to wait for S&T to come and fix it! Last edited: 28/08/2013 at 17:24 by Danny252 Log in to reply |
| Manually changing points in anticipation of setting route 28/08/2013 at 20:49 #48959 | |
pedroathome
915 posts |
" said:I believe that a typical AC induction motor (Not sure what types are used on the railways) uses somewhere around 5 times more current during start-up than when running James Log in to reply |
| Manually changing points in anticipation of setting route 28/08/2013 at 21:01 #48960 | |
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Firefly
521 posts |
Quote:believe that a typical AC induction motor (Not sure what types are used on the railways) uses somewhere around 5 times more current during start-up than when runningThe majority of point machine are driven by 120v DC. not sure if the same applies, it's all way beyond me. FF Last edited: 28/08/2013 at 21:02 by Firefly Log in to reply |
| Manually changing points in anticipation of setting route 28/08/2013 at 21:08 #48962 | |
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Firefly
521 posts |
The problem with reducing the size of the cables and the ratings of the transformers is that you then have to guarantee that points won't be moved at the same time. This then requires additional interlocking which would represent an increase in design and testing cost. It would be a bit of a nightmare if the signaller swung a set of points just as the ARS set a route and all of a sudden you've blown the supply to several signalling locations FF Log in to reply |
| Manually changing points in anticipation of setting route 29/08/2013 at 05:21 #48971 | |
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Hawk777
386 posts |
Yes, the same applies to DC motors. *All* electric motors generate back EMF when spinning, and it’s the lack of back EMF when stationary that causes the power spike. In fact, many motors will burn themselves up if you apply their rated voltage and don’t let them turn—their stall current (current drawn when stationary and rated voltage applied) can be much higher than their continuous rated current (maximum current you’re allowed to send in forever and expect the motor not to overheat)!
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| Manually changing points in anticipation of setting route 29/08/2013 at 09:33 #48985 | |
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kbarber
1743 posts |
" said:" said:Aha....as I thought so Sorabain plan to manually key points will backfire at some point (no pun intended!).....But I can see what Sorabain wants to do, and I've done the same on Stafford (particularly when I'm running with the Gremlins). Of course the Stafford boxes themselves, the pointwork at Colwich (but not Rugeley or Armitage - they were worked from a panel in Colwich) and the boxes at Lichfield, Tamworth & Hademore were mechanical frames. There is a theory that levers should be restored to their normal position after a train has passed (honoured more in the breach than the observance I hasten to add, without comment from the inspectorate). But more to the point, the REC frame and its BR(LM) derivative found in Stafford 4 & 5 and Colwich had levers that came over a very long way; sometimes it was worth restoring points levers to get them out of the way as you worked up & down the frame, especially those whose reversal was uncommon. The alternative was to risk coming into contact with one you weren't used to walking around, usually at an uncomfortably high speed as you headed off down the frame to answer a bell; I can assure you the result was an eye-watering reminder that the lever needed normalising! Tamworth, Lichfield and (I think) Hademore were LNWR boxes with Webb frames; the levers in those didn't come so far over, so leaving points reversed until next required to be changed would be less potentially painful. My practice was to leave frequently-used points where they were last set until they needed moving again (and where I had a Derby frame to get used to where those levers were) but to normalise rarely-used points and those leading to/from sidings/yards (anything protected by a trap point, basically) unless I had reason to think the next move would require them reverse. Log in to reply The following users said thank you: sorabain, Gwasanaethau |
| Manually changing points in anticipation of setting route 29/08/2013 at 11:22 #48987 | |
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jwsetford
164 posts |
If the points are right next to each other it can result in a derailment. I discovered this when on my model railway a freight train was crossing from one track to another derailed because the bogies were trying to go in two directions in one. So it means the train might moan it has ran out of valid track.
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| Manually changing points in anticipation of setting route 30/08/2013 at 02:58 #49009 | |
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indian_railways_fan
72 posts |
On the Indian Railways,where Siemens practice of interlocking is extensively prevalent,all Route Relay Interlocking(RRI)/Route Setting type installations are provided with Point "Chain" groups.These are pre-wired relay groups which are interconnected with the point group in such a way that whenever a route is initiated,at a time only two sets of points will be allowed to operate and the next set of points will started only after the previous two points' initiation(but not the detection)stage has been completed.In this way,the "kick load" or starting current of the points is kept in control to avoid overloading of the power supply system. In addition,the points on a double-ended crossover are operated in series.First one machine will operate and if it completes detection,the supply is extended from this machine to the second machine which on completing operation and detection will operate the appropriate relays in the point-group to switchover from operating mode to detection mode. Khalid. Log in to reply The following user said thank you: Firefly |