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| Manually changing points in anticipation of setting route 26/08/2013 at 23:47 #48884 | |
arabianights
138 posts |
Occasionally, when it's not possible to set a route because of interlocking but it is possible to set (at least some of) the points for that route, I do so because this will mean the signal will clear quicker as I don't have to wait for the points to change. Is this done in RL and in general is it considered good or bad practice? Log in to reply |
| Manually changing points in anticipation of setting route 26/08/2013 at 23:58 #48885 | |
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Hooverman
306 posts |
I only manually swing points to force swinging overlaps to go in the direction that I want if I see a potential conflict. We also have some routes that will only set once the points have been swung a certain way first. Other than that I leave the IPS alone except for passing signals at danger. Oops how can I forget those annoying points normalisation alarms that need the points swung normal to silence then!
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| Manually changing points in anticipation of setting route 27/08/2013 at 00:29 #48886 | |
DriverCurran
688 posts |
" said:Oops how can I forget those annoying points normalisation alarms that need the points swung normal to silence then!Quite easily, nice set of headphones and start saying "la lala lala la" very loudly above the volume level of the normalisation alarms :p Paul You have to get a red before you can get any other colour Log in to reply |
| Manually changing points in anticipation of setting route 27/08/2013 at 08:22 #48891 | |
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Hooverman
306 posts |
" said:" said:Lol, good try Paul but there will be at least eight other colleagues plus shift managers to remind me of the noise pollution, with lots of tuting. :-)Oops how can I forget those annoying points normalisation alarms that need the points swung normal to silence then!Quite easily, nice set of headphones and start saying "la lala lala la" very loudly above the volume level of the normalisation alarms :p Log in to reply |
| Manually changing points in anticipation of setting route 27/08/2013 at 13:14 #48894 | |
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Firefly
521 posts |
To be honest there's little point in doing that. When you set a route all points in the route are "called" at the same time, all will move together. It doesn't matter if it's 1 set of points moving or 20 sers, the route will set just as quickly. Obviously each set moves at it's speed depending on age, switch / slide chair condition, machine type etc but the difference in each set is only going to be 1-2 secs max.
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| Manually changing points in anticipation of setting route 27/08/2013 at 15:36 #48896 | |
postal
5264 posts |
" said:To be honest there's little point in doing that. When you set a route all points in the route are "called" at the same time, all will move together. It doesn't matter if it's 1 set of points moving or 20 sers, the route will set just as quickly. Obviously each set moves at it's speed depending on age, switch / slide chair condition, machine type etc but the difference in each set is only going to be 1-2 secs max.According to July Modern Railways things are now starting to change on smaller less intensively worked installations (although not yet relevant to most of SimSig). This is a snip from the article reviewing the recent Norwich - Ely changes: [indent]Points Another power saving strategy is to sequence the switching of points. In a busy junction with conventional signalling, when a route is set all the point motors go to work at once with the aim of setting a route in, typically, 10 seconds. As a result the point motors create a peak in electric power demand. With the simpler layouts and lower service frequencies on Mod-Sig applications, fast route setting is not an issue. As a result, when a route is set on Ely-Norwich, the point ends move one-at-a-time in sequence.Thus the capacity of the REB's power supply is determined by the consumption of one point motor rather than the number of points in the island. Another break with accepted practice is driving points at up to 700 metres from an island. Normal practice is around 200 metres maximum.[/indent] “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 Last edited: 27/08/2013 at 15:39 by postal Log in to reply The following user said thank you: Firefly |
| Manually changing points in anticipation of setting route 27/08/2013 at 16:08 #48899 | |
Steamer
3984 posts |
" said:What's an Island in this context? "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Log in to reply |
| Manually changing points in anticipation of setting route 27/08/2013 at 16:18 #48901 | |
GeoffM
6376 posts |
" said:" said:I'm struggling to see how moving two or more point machines sequentially rather than in parallel will actually save power overall. In addition, Ely to Norwich resignalling (which I believe does not include either of the two stations but just the bit in between) is very simple with few point ends. Possibly setting two independent routes in the same area would cause a staggering of point movements. But saving power? Limiting demand at a single moment in time, yes.To be honest there's little point in doing that. When you set a route all points in the route are "called" at the same time, all will move together. It doesn't matter if it's 1 set of points moving or 20 sers, the route will set just as quickly. Obviously each set moves at it's speed depending on age, switch / slide chair condition, machine type etc but the difference in each set is only going to be 1-2 secs max.According to July Modern Railways things are now starting to change on smaller less intensively worked installations (although not yet relevant to most of SimSig). This is a snip from the article reviewing the recent Norwich - Ely changes: " said: " said:I believe it's simply a cluster of signalling equipment. I've only heard of it referred to for this type of modular signalling. I've heard it on Shrew to Crewesbury* as well.What's an Island in this context? * an in-joke. SimSig Boss Last edited: 27/08/2013 at 16:19 by GeoffM Log in to reply The following user said thank you: Steamer |
| Manually changing points in anticipation of setting route 27/08/2013 at 18:05 #48907 | |
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postal
5264 posts |
" said:I'm struggling to see how moving two or more point machines sequentially rather than in parallel will actually save power overall.Yes indeed. More than likely the result of letting loose non-technical journalists on hard subjects. As you say, reduction in peak demand rather than reduction in power. “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 27/08/2013 at 18:38 #48909 | |
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AndyG
1842 posts |
" said:I'm struggling to see how moving two or more point machines sequentially rather than in parallel will actually save power overall.The saving is not the power consumed, but a cheaper installation costs due to lower (peak) current demand, so a thinner supply cable and switchgear etc. Bit like having to fit a thicker supply cable for an instantaneous shower, rather than a smaller cable to heat up a storage tank. Less amps for a longer period, but power used is the same. I can only help one person a day. Today's not your day. Tomorrow doesn't look too good either. Log in to reply |
| Manually changing points in anticipation of setting route 27/08/2013 at 18:57 #48911 | |
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postal
5264 posts |
" said:" said:A long time ago I did A-level physics and when I go back to that I realise that I wrote absolute tosh in the previous post.I'm struggling to see how moving two or more point machines sequentially rather than in parallel will actually save power overall.Yes indeed. More than likely the result of letting loose non-technical journalists on hard subjects. As you say, reduction in peak demand rather than reduction in power. From first principles, work refers to an activity involving a force and movement in the directon of the force. To do this work you expend an equivalent amount of energy. Power is the rate of doing work or the rate of using energy, which are numerically the same. So if each point movement requires 1 unit of work to move the blades and there are 10 points to move, 10 units of work will be done and 10 units of energy will be required. If the movement takes 1 second and the movements take place simultaneously, then 10 units of work will be done over 1 seconds, i.e. the power used will be 10 units per second. The power usage will be 10 units expended over 1 second or 10 unit-seconds (analogous to kilowatt hours on the electricity bill). If the point movements take place sequentially, then 10 units of work will done over 10 seconds i.e. the power used will be 1 unit per second - a reduction of 90% in the power. However, the power required in total will still be the same at 10 unit-seconds. Apologies for previous academic inadequacy and disrespect for technical journalism which is quite correct in this case. “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 27/08/2013 at 21:07 #48913 | |
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arabianights
138 posts |
bit scary for GCSE standards if A level physics is needed to understand that
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| Manually changing points in anticipation of setting route 27/08/2013 at 22:35 #48917 | |
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GeoffM
6376 posts |
" said:A long time ago I did A-level physics and when I go back to that I realise that I wrote absolute tosh in the previous post.Not sure what's wrong with your previous post. I think we're all agreed that the 50p pieces in the electricity meter are the same, it's just the beefiness of the power supply required to drive them all. I suppose the original quote "power saving" could be referring to the peak power consumption rather than the overall power consumed, though I would think the average reader would interpret that as money off the electricity bill, not thinner wires/fuses etc - which is perhaps what the author of said quote wanted the average reader to believe. SimSig Boss Log in to reply |
| Manually changing points in anticipation of setting route 27/08/2013 at 22:52 #48918 | |
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Lardybiker
771 posts |
" said:" said:The confusion here is what was meant by "power-saving" in the article. Most people will read that article and assume that it means NR are saving money on their electric bill by running points sequentially and by doing so they have confused "power-saving" and "energy-saving" as we use phrases like "power-saving" and "energy-saving" pretty much interchangeable in our every day language." said:A long time ago I did A-level physics and when I go back to that I realise that I wrote absolute tosh in the previous post.I'm struggling to see how moving two or more point machines sequentially rather than in parallel will actually save power overall.Yes indeed. More than likely the result of letting loose non-technical journalists on hard subjects. As you say, reduction in peak demand rather than reduction in power. That said, electric bills are calculated using the amount of energy you use, not power so "power-saving" and "energy-saving" are not, by the physics definitions, the same at all...... Power is measure of energy per unit time. If you have ten points working over 1 second then the power required is a much greater value than if you run the one point at a time over 10 seconds so in the true definition of the phrase, the article is correct and they are power-saving...... However, the energy required to move those same points is still the same no matter what and it's that energy that's measured by the electricity companies and consequently, what the bill is based on. In this case, it doesn't matter how you move the points, all at once, in two lots of five, or 1 point at a time, the energy required to move all 10 is exactly the same and the corresponding electricity bill will be EXACTLY the same. Log in to reply The following user said thank you: postal |
| Manually changing points in anticipation of setting route 27/08/2013 at 23:04 #48921 | |
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vontrapp
210 posts |
Far from saving time in pulling-off, saving my/our legs was a priority. On Absolute-Block, if we had a train accepted from the SB in rear and the advance SB cleared-out for another train, we would pass the train on, although no TES had been received. At one SB we did pass the train on officially and gave 1.2.1 on receipt of TES. This could have led to confusion when one had to warn the other box to work 'straight-up' (1.2.1). The way of sending the 'Boss Approaching Signal' was to send 1.2.1 'wrong-line' to the SB in rear on the SL block.
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| Manually changing points in anticipation of setting route 28/08/2013 at 11:14 #48925 | |
outofsection
149 posts |
It isn't just a case of moving 10 sets of points at once requires 10X the power! There's also the very brief high power surge to allow for that each point motor gulps from the supply at the moment of energizing - and that's in addition to the motor having to overcome the inertia of the points mechanism. By staggering the moving of all the points, although the TOTAL energy drawn from the supply is the same, the instantaneous energy drawn from the power supply is dramatically reduced. Here's why:- When any motor starts from rest, it initially draws a very high current. Once the point motor is up to speed, the current flowing through the motor falls considerably. 10 sets of points energizing at the same instant would produce a HUGE (momentary) power demand spike on the power supply which, if it's not rated highly enough, may cause damage to components in the supply such as rectifiers (if used) and fuses/trips etc.. This is due to Lenz's Law which very much simplified means that when a motor is at rest and then has power applied to it, the power drawn is very high momentarily. Once the motor is turning, the power drawn by the motor reduces dramatically as the motor in effect also becomes a generator or dynamo, and the nature of this generated voltage opposes the flow from the power supply thus reducing the flow of current through the armature (the part of the motor that rotates) coils. This reduction in current continues until the motor speed, the physical load on the motor and the current flowing through the motor reach a balance where the motor is said to be running at the maximum speed it can. To increase the motor speed further, the current flowing through the armature coils must be increased further, or the current flowing through the field coils has to be reduced. The latter option whilst increasing speed, reduces the torque (power) produced the motor. This principle was used to great advantage in early direct current electro-mechanical speed/power control circuits used on electric trains/trams where the driver or motorman, when stopped at a station, would via a switch in the cab which operated various contactors, switch the connections in the motor circuit from parallel working to series working where the armature coils and field coils(s) of the motor(s) are connected in series with each other. This gives an initial very high starting magnetic field strength to enable the armature to provide maximum starting torque. As the train increased in speed and thus the current through the armature coils of the motors reduced, so did the current flowing through the field coils. Above a certain speed the motorman would switch to parallel connection where the field coils & armature coils would be connected in parallel with each other which would enable the use of a bank of field current diverting resistors to be used to reduce the current flow still further through the field coils in the motor and thus weaken the magnetic field even further which would enable the motor(s) to run even faster as the opposing voltage generated by the armature coils turning is reduced as a result of the weakened magnetic field around the armature coils. The resulting loss of torque in the motors is no longer such an issue at high speed as the momentum of the train helps compensate for the reduced torque output of the motors. As the meerkats would say... Seemples! The total energy drawn from the power supply is the same whether you operate all 10 sets of points at once or stagger them, but the important advantage is that by operating the points sequentially the INSTANTANEOUS power demand on the supply is reduced by 90%, but the downside is that the time taken to effect the operation has increased 10-fold. However, the TOTAL energy used is the same in either case as energy = the amount of power drawn multiplied by the time over which it's drawn. Here endeth today's physics lesson! Last edited: 28/08/2013 at 12:17 by outofsection Log in to reply The following users said thank you: Steamer, postal |
| Manually changing points in anticipation of setting route 28/08/2013 at 11:44 #48927 | |
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clive
2789 posts |
" said:Because, I'm afraid, *you* are confusing power and energy. If a points motor requires 50W for 5 seconds (numbers made up here), then it requires 250J of energy. If you have two such motors, you require 500J of energy. It doesn't matter whether you run them sequentially or in parallel. HOWEVER, if you run them in parallel you need 100W of power. If you run them sequentially you need 50W. That's a power saving, which means thinner cables and other related benefits (I used to work somewhere where they got billed by the electricity board for maximum power over the month as well as the energy consumed, so rescheduling things saved thousands of pounds a year). Household equivalent: boiling ten kettles of water uses the same number of units on the meter (energy) no matter whether you do them at the same time or not. But if you try to do them all at once you'll pop the breaker in your consumer unit (too much power). Log in to reply |
| Manually changing points in anticipation of setting route 28/08/2013 at 11:53 #48928 | |
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clive
2789 posts |
" said:A long time ago I did A-level physics and when I go back to that I realise that I wrote absolute tosh in the previous post.Right so far. Quote: No. The energy usage will be 10 units. The power usage will be 10 units per second. Your units are energy (so joules) and the concept "unit-seconds" has no physical meaning. Quote: Right. Quote: No, the power required in total will change. The *energy* used will be the same at 10 units. You're being confused because electricity bills are labelled in "kilowatt-hours", which is power times time, which is energy. If you wanted to express your statement like that, then you need to say: "So if each point movement requires 1 unit of power to move the blades and takes one second, then it uses 1 unit-second (equivalent of kilowatt-hour on the electricity bill) to move the points. If there are 10 points to move, 10 unit-seconds of work will be done and 10 unit-seconds of energy will be required. If the movement takes 1 second and the movements take place simultaneously, then 10 units of power will be used over 1 second, while if they're done sequentially then 1 unit of power will be used over 10 seconds. Both result in 10 unit-seconds of energy." Log in to reply The following user said thank you: postal |
| Manually changing points in anticipation of setting route 28/08/2013 at 12:08 #48929 | |
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Jan
906 posts |
To further complicate matters, maybe a small saving of power could be achieved because the power supply is, while it is being used, always running at its nominal rating: Either it's powering one set of points, or else it is off, while on a conventional scheme, it could be required to power any number of points at a given time. So if you have only one level of power demand, you could then gear your power supply to run at maximum efficiency at precisely that load. I have no idea though how much of a difference that would actually make. Two million people attempt to use Birmingham's magnificent rail network every year, with just over a million of them managing to get further than Smethwick. Log in to reply |
| Manually changing points in anticipation of setting route 28/08/2013 at 12:18 #48930 | |
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Late Turn
699 posts 
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" said:Far from saving time in pulling-off, saving my/our legs was a priority. On Absolute-Block, if we had a train accepted from the SB in rear and the advance SB cleared-out for another train, we would pass the train on, although no TES had been received. At one SB we did pass the train on officially and gave 1.2.1 on receipt of TES. I've always considered it good practice to try to group bell signals in that way, especially in a busy box. Although it's unofficial, I've seen at least one document which says that it's a good idea. Care needs to be taken to avoid pushing them too far though! We have quite a few boxes on our section that are authorised to offer forward immediately, and one that offers forward on receipt of 1-2-1, so there's quite a bit of flexibility there...the rest tend to act as holding boxes; one tends to work absolutely straight up as the train would otherwise be pushed rather a long way! Log in to reply |
| Manually changing points in anticipation of setting route 28/08/2013 at 12:26 #48931 | |
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outofsection
149 posts |
It means you can specify the power supply to provide a much lower power output (and thus save a considerable amount of money in doing so) as you'd only need a power supply that gave a continuous power output of 1/10th of the power output needed if you operated all 10 sets of points simultaneously.
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| Manually changing points in anticipation of setting route 28/08/2013 at 13:30 #48935 | |
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sorabain
72 posts |
Regarding the original query I quite often re-normalize points where things aren't particularly busy but the last route had set the points to some "uncommon" direction and i'm worried that when the next service rolls in and I try and set a route through it i'll end up with a points failure right at a bad time. If they decide to fail when no trains are around at least the engineer gets a head start trying to fix it! Maybe it's a little paranoid, i think i got stung on Stafford a few times that made me start doing this. Log in to reply |
| Manually changing points in anticipation of setting route 28/08/2013 at 16:31 #48945 | |
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Lardybiker
771 posts |
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!! At the end of the day, the point motor is doing the same thing regardless whether you change them by keying them manually or change them by setting a route. The interesting question for Clive or Geoff at this point then is to ask.... Is SimSig programmed such that point failures can occur if a point is manually keyed? Log in to reply |
| Manually changing points in anticipation of setting route 28/08/2013 at 16:51 #48947 | |
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GeoffM
6376 posts |
" said:The interesting question for Clive or Geoff at this point then is to ask.... Is SimSig programmed such that point failures can occur if a point is manually keyed?Yes! SimSig Boss Log in to reply |
| Manually changing points in anticipation of setting route 28/08/2013 at 17:05 #48949 | |
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Lardybiker
771 posts |
Aha....as I thought so Sorabain plan to manually key points will backfire at some point (no pun intended!)..... Edit: Thanks Goeff for the quick clarification Last edited: 28/08/2013 at 17:06 by Lardybiker Log in to reply |