I'm going to answer your questions in some detail - nit just because I like to waffle - but - because they are very good/useful questions - and other modellers looking at this might benefit by my waffling... Or they may just use it to cure insomnia.
QUOTE (Danny Vanstraelen @ 20 Aug 2016, 21:11)
<{POST_SNAPBACK}>@Bear 1923
My dear friend that was quite an answer
First of all, the books are on the book list, they all look very interesting, especially the first one.
Lewis is certainly very useful
(I have possibly just put up its auction price...
).
QUOTE
What I'm looking for is the way they are placed, left side of the track to which they apply (as seen by approaching train crew) and over the track as far as the centre line is standard. Anything placed further right is "Wrong Side". Signals can be wrong side - but - there has to be a good reason for it.
This I understand, it's basically the same as here in Belgium as we copied the British system.
Do you run on the left as well? I suspect that some of your early signalling equipment my have been bought in from the UK?
Of course running on the left is running on the right side.
QUOTE I bought a few Ratio kits of LNER signals.
Not necessarily the "best"/most accurate as models - but - for your scheme probably sensible. Have you used 00 in the garden before? It's unusual - but - not impossible.
QUOTE And my question of placement concerns particularly the "Bracket" type of signals.
That the arm on the pylon itself of the distant signal points to the right, that would make sense.
but if you look at the pylon of the home signal points to the left does not make any sense to me.
Why isn't that pointed also to the right?
Or is the pylon placed right in this case, but due that the arm hangs over the line , it must be seen as standing on the left?
From a purely physical point of view, taking posts planted to the left of the track to which they apply...
A bracket to the right can be used to push the doll and consequently the signal arm (or head for a Colour Light {CL}) out over the centre line of the track. This can occur due to the line ahead of an approaching train being curved to the left. It can also occur due to a structure between the approach and the signal tending to obscure the sighting of the signal- this can be any structure (including outside the boundary). The more usual structures to cause this are platform canopies and passenger footbridges. There is a third possible cause - this is less obvious - but - I'm sure that as a Driver you will be aware of it - it is the background of the signal - as in - you need a nice clear look at the indication - without anything beyond it confusing the issue. Semaphore signals can have a "sighting board" behind them to assist - this can be provided on any signal structure. Different companies used different designs. (CLs can have a sighting board as well - but it is far less common).
A bracket to the left is appropriate for the same reasons - curvature to the right being the first case. Sometimes, where ground space is available, the signal post will simply be placed further to the left of the rail head than usual. A bracket may be used when the ground is not clear. With CLs it is more common than with semaphores for signals to be sat up on top of retaining walls to the left of the track. As always the over-riding issue is that the crew will get a good view of the signal - as I'm sure you appreciate. As far as structures go - the big cause of bracketing to the left is to put the signal over the centre line of the track where there is a structure on the right hand side - and probably a lack of space on the left hand side... This occurs largely with island platforms and for "turn back" signals - "Turn Back" signals are those where trains terminate on a through line and start back from the same platform - this is massively more common with CLs than with semaphores - this is a direct consequence of the differences between line-of-sight/mechanical signalling and train detection/track circuit signalling. The requirements (limitations) of mechanical interlocking make a Turn Back far more difficult and costly than the capabilities of relay interlocking.
Brackets that put the signal out to a position half way over the track to which they apply are pretty straightforward. Brackets can also have a longer reach. It is not unusual for a longer bracket to reach over a siding or loop line to achieve a Stop Signal being placed in the correct place for the Running Line. Similarly the signal for a fast line might be bracketed out over a slow line. This can also be worked the opposite way around. Where there is nowhere for a post to be planted on the left side of the track a bracket may be used from the right with a longer reach extending over the opposite line - or again - the extension may be over a line in the same direction.
Once we consider this it all seems horribly obvious - except that it isn't obvious - until it is "obvious". Why go to the expense of a large bracket structure if it's only to get the signal into place and it doesn't add meaning to the signal? The logic is mostly found in the history of where the signal is and when it was put there. As I've said, this begins with the original track arrangement not being designed to be signalled. Subsequently re-arrangement of the track - additions and extensions in particular - can create causes for inventive ways of getting the signal where it needs to be. Then again - further developments can leave a signal looking strangely over-built - this is usually the reduction of tracks.
Another factor impacting on signal placing and therefore signal structures is the speed capacity of trains. I'm sure that you know that signal placement is directly related not to the higher speed capacity of trains but to their capacity to stop.
I hope that this makes things clear.
QUOTE
l and speeds connected to certain signal images. UK Signalling is "Route Signalling" using "Position Value" for semaphore - NOT "Speed Signalling"
Ok, I do understand that a signal doesn't give you a speed limit like a road sign, but I can't believe that a train that sees a closed distant signal could run up at any random speed to the home signal?
Or lets say you have a series of home & distant combined signals.
And the distant signal is each time closed, in such a case we are not allowed to go over 40Kmh here in Belgium, Germany has a similar rule, isn't this also the case in the UK?
As before - a Distant signal that is "On" - at "Caution" instructs the train crew that the associated Stop Signal(s) are also "On" and that speed must be reduced so that the train can be stopped dead before it reaches the next/first associated Stop Signal.
I have to keep referring to an "associated" Stop Signal due to Slotted Distants. In the case of a slotted Outer Distant the instruction will apply to the first Stop Signal of the next group of Stop Signals and not the Stop Signal over the slotted Inner Distant. Things are so much easier when colour light signals are used! (So long as you don't get involved with GWR usage of Searchlight signals!)
So... The key is to look at where Distant signals get used.
Distants - rather than Repeater Signals in CL/TRack Circuit Block) - are a feature of Absolute Block and its derivatives. (I am not going to deal with derivatives).
In AB the line is divided into Block Sections and Station Limits.
Station Limits are the lines from the first Stop Signal to the last Stop Signal in each direction of the one Signalbox that is a Block Post. At the usual maximum length this will be from the Outer Home to the Advanced Starter. The Advanced Starter will be the Section Signal - entry into the Block Section ahead.
The Block Section id therefore the line - in one direction only - from the last Stop Signal/Section Signal of one Block Post Signalbox to the first Stop Signal of the next Block Post that is "open" (i.e. switched into the Block Circuit system).
Distant Signals, occurring on the approach to the Stop Signal(s) to which they apply are therefore inside the Block Section.
Distant Signals enable approaching trains to maintain speed without signal-check whenever they are "Off" indicating "proceed"... Being interlocked so that they can only show "Off" when all the associated Stop Signals are also "off" means that an approaching crew knows that all the Stop Signals of the Station Limits are also "off" at the time of sighting the Distant and that they can therefore proceed straight through the Station Limits into the Block Section beyond the Station limits. This does not effect any station/platform stops, stops for water (steam engines) or any other activity that a train may need to achieve in Station Limits. The Distant simply says that all the Stop Signals are "off".
A Distant Signal being "off" does not mean that all the Stop Signals will still be "off" when the train arrives at them. An emergency may cause the Distant to be put back "on" and the Stop(s) to be put on before the approaching crew reach the first Stop Signal. This can result in a SPAD - "Signal Passed at Danger". It also tends to cause train crew to need to make a change of trousers. An approaching crew seeing a Stop against them after the Distant was clear will make a lot of noise on the whistle/horn. They are likely to make further, verbal, noise after they have stopped safely. For some reason crews running on clear signals get upset if they have them "put back" on them.
Distants are placed at a calculated Standard Braking Distance (SBD) from the first Stop Signal to which they apply. The SBD is calculated on the line condition, gradient, curvature and the permitted speeds of trains on the line. The permitted speed may be adjusted (downward) to accommodate issues relating to the SBD.
Where signalboxes (not necessarily Block Posts) are located close together along the line the SBD of one box may run into the signalled area of the box on the approach to it. In this case the Distant Signal for the second box approached will be placed under the last Stop Signal of the first box. Put simply - if there are two non-block level crossing boxes close together the Distant for the second one will be under the Stop Signal of the first.
Once we deal with Block Post Boxes we can get Inner and Outer slotted Distants under consecutive Stop Signals of the first Box approached.
When boxes are extra close together the 2nd box's Distant may be combined with that of the first box. (Slotted with it).
See what happens when you ask questions?
QUOTE 0r at the first movement of a train, it basely can't run at full speed, until it sees it's first home signal.
Isn't there a speed limit then?
Okay... Leaving a Station Limits a train can run through the Block Section at any speed up to the PSR (Permanent Speed Restriction) that is safe until the Distant Signal of the next (open/working) Station Limits. When the Distant is sighted the speed will depend on whether it is "on"/at caution/ "against" the movement - in which case speed must be reduced as described --- OR - the movement can carry on at any safe speed up to the PSR through the Station Limits.
(When the Signalbox/Block Post of a Station Limits is switched out of circuit it doesn't exist as far as the Block System is concerned. The relevant signals on the track have to all be left in the "Off" position to avoid unduly delaying trains.
I should comment that, while there is much descriptive complication in both modelling and real railway literature, there is a distinct difference between a Home Signal and a Stop Signal. Basically, ALL signals that can show a Red aspect are Stop Signals. Home Signals are only those signals on the approach side of a Signalbox (whether it is a Block Post or not). Stop Signals beyond the Signalbox/Block Post are "Starters". (This is so long as you don't get into LMS practice - they called all their Stop Signals Homes except for the last Stop Signal/Section Signal... But then - the LMS are always difficult!)
QUOTE And how are speeds of a certain line given at that time?
So... Adding to the above... When a Stop Signal is cleared a crew may move at any safe speed up to the PSR with whatever acceleration they can achieve. Their
Route Knowledge will tell them where the next Stop Signal to look out for is. They will know whether they are within Station Limits and therefore need to look out for the next Stop Signal immediately or they are entering the Block Section - in which case their next Stop Signal may be very close - or - several miles ahead. In addition - when in a Block Section they will have the Distant Signal to look out for.
This deals with Stop Signals - which are Running Signals. Running Signals are - in the words of our training schools - the signals controlling movements that are making journeys - "going from town to town". Put another way - they are the big signals that can be seen in good time by crews approaching at speed.
Then there are Non-Running Signals. These are all the little signals - shunts and subsidiaries -(the "miniature" arm misnamed in the Ratio document). These are often Ground Signals or small arms placed under Stop Signals. they are all the signals that don't want to be seen by crews moving at speed in Running Movements.
Running Signals, when showing proceed, permit movement up to the PSR. The line from one Running Stop Signal to the next will be clear for movement. (Unless an uncontrolled emergency occurs - which is why you have to keep looking at the line ahead).
Non-Running Signals, when showing proceed, ONLY permit movement at a speed allowing the movement to stop dead short of any obstruction.
The results are...
Drawing past a Running Signal that is off a crew can go up to the PSR immediately. Drawing past a Non Running Signal the crew have to proceed with caution, prepared to stop dead.
For this reason a cleared Running Signal/Stop Signal always gives approach to another Running Signal/Stop Signal - except when running onto buffer stop lights in a passenger terminal. (A multiple aspect CL Running Signal will only give a Yellow aspect in this situation).
A Non running Signal may give approach to either a Running Signal or a Non running Signal. When the first occurs the movement must be made at caution until the Running Signal is approached - when that signal must be obeyed.
QUOTE Here in Belgium we have plates next to the line, that indicate the speed you aloud to go.
In Germany they work with a book, that you read as a map so to speak, and this book point out the max. speeds for that particular train.
Very difficult and not paper friendly, although we have an electronic system now, you still have to have the paper version with you in case of electronic failure.
I covered this before.
QUOTE Anyway thank you all for the response.
Cheers,
Danny
That's okay.
Good questions give me practice at explaining - and hopefully getting better at it...
