Hello All,

Re three position Low Speed signals . Low Speed signals take you from either a station to a siding , a siding to a station , a running line to a running line , a siding to a siding , or into a crossing loop . They may also be fitted to a Home Signal to bring a train into an occupied road , as a calling on signal.

Where a Low Speed signal is on a Home Signal ( which protects Stations , Sidings , Signal Boxes , Level Crossings and Junctions ) the Home Signal will display Red over Red in a vertical line.

The Low Speed will be non illuminated black. Once the Low Speed Signal is initiated , either by the Signalman , or by a timing circuit that ensures the train is either at, or nearly at, stop ; the Low Speed will illuminate a small Yellow. The Low Speed light ( always a light when mounted on a Home Signal ) is vertically below the two red lights.

Home signals may also be equipped with an illuminated route indicator , usually to the left of the Low Speed ( there are exceptions ) . The indication is usually a letter , sometimes an arrow . In the event of there being more than one route indicator on the post they will be fitted adjacent to each other and below the Low Speed ( there are exceptions ).

Best wishes and regards, Radioman

Hello All,

Re three position dwarf signals.

Three position Semaphore  signals consist of a white target with a red arm with white bar painted there on. They operate in the upper quadrant and display a red or purple light with the arm horizontal . Low Speed Warning is a yellow light with the arm raised 45 degrees. Clear Low Speed is a green light with the arm raised 90 degrees.

Low Speed Warning , Yellow light means the route is locked but the line ahead may be obstructed.
Clear Low Speed , Green light , next fixed signal at proceed, speed not to exceed 15 kph.

Dwarf light signals usually have only two lights where the lower light displays Red or Purple , and the Upper light Yellow.where a dwarf light signal could display a Green light this was ( at least until recently ) a miniature searchlight signal.until the closure of Melbourne Yard , this place was ( so I was told ) the only place that a Clear Low Speed signal could be observed. ( this may have recently changed ) .

Best wishes and regards, Radioman

Hello All ,

Re three position dwarf signals again.

The provision of a Purple light in lieu of a Red light was to make dwarf signals easily distinguishable from Home or Automatic signals at night.

When the VR began installing colour light dwarf signals , the purple light could be blotted out by sunlight during the day , so purple lights began to fall out of favour.

However , the arrival of bright LED ( Light Emmitting Diodes ) for signalling purposes meant that Purple lights again came into favour.

However, it was found that Purple LEDs were not really purple , but in actuality were Blue . Solution to problem , a SW Notice was issued to the effect that Blue light are Purple for the purposes of signal indications . Problem solved !

The VR was also quite keen of having disc ( two position only ) and dwarf signals post mounted wherever possible , so as to be in the driver's line of sight . The obvious exception was disc or dwarf located between two running lines, usually for shunting purposes .

Best wishes and regards, Radioman

Hello All,

Yet more on dwarf signals.

When Epping Maintenanxe Depot was built , at some point a decision was made to provide only ground based dwarf signals within the Depot. A lot of drivers were not happy, as ground based signals are not only a tripping hazard , especially during hours of darkness , but drivers need to clearly see the signal from the cab. Hence drivers parked the trains some way to the rear of the signal to ensure a clear view . In some cases the parked train prevented the following train in the rear ( the sidings were long enough to hold two six car sets ) was unable to clear the rear track circuit and thereby prevented the points from being normalised.

The arrival of the Alstom Xtrapolis sets compounded the problem because it was not possible to see the dwarf signal from the cab unless the train was halted some distance to the rear of the signal . Eventually the existing dwarf signals were mounted , at great expense due to the rewiring required , on posts so that drivers could clearly see, and move up close to the now post mounted dwarf signals.

Best wishes and regards, Radioman

Any Driver who 'parked' anything except where it was supposed to be would be VERY unpopular and leaving the rear 'hanging out' would see him (no 'Her' then) spoken to very severely particularly if it was track circuited and affected anything.
Unless directed otherwise, ANYTHING had to be brought to as near as possible to a signal or clearance point.
Ground signals varied in height and shape, old ones with semaphore arms, newer with a banner or colour lights but during my brief time as a Shunter, I always made sure I rode high to avoid hitting it.

Dear Gordon S 1942 and others ,

Yes , Gordon you are correct , but the situation that arose at Epping had not been anticipated. It was the arrival of the Xtrapolis sets that highlighted the problem.

The Epping Maintenance Depot sidings are quite long , so the second train would still be in clear on the siding yet may still sit on the rear track circuit . As Epping is fully signalled , Shunters are not required .

I understand that measures were put in place to prevent a recurrence , but the problem still remained that drivers could not see the ground based dwarf signal due to the cab design of the Xtrapolis trains.

The problem also would not have arisen if the dwarf signals were post mounted as was past practice.

The newer trains in Victoria , Alstom Xtrapolis and Siemens Networkers cab design has the driver sitting further back from the control desk and the front of the train than previous versions . This has resulted in a number of signals being modified or had co-acting arms added to allow the driver to clearly observe the approaching signal.

Best wishes and regards, Radioman

'The problem also would not have arisen if the dwarf signals were post mounted as was past practice.'

Back in antiquity, I always thought that dwarf signals were, more or less anyway, ground mounted.

Never ceases to amaze me that the brains of privatisation could buy trains from which drivers were unable to see the signals.

Even more amazing is that we continue to buy these trains which are still unsuited to large sections of the suburban network.

Hello All ,

As a retired VR signalman , the Repeating signal , Green over Yellow was on the boundary from a two position to a three position signalled area , hence its placement at Oakleigh .

I was not aware of any repeating signal at Oakleigh during the period it was a 2-pos station, with 3-pos signalling in the up direction. Where was it located?

Up trains departed Oakleigh with 2 position LQ signals at the platform ends (4 signals, 3 platforms plus the centre road), and the next signal was auto D474 between there and Hughesdale.  

At the time John Sinnatt wrote Clear Normal Speed (published 1966) he stated there were repeating signals at Viaduct Junction and North Melbourne (Goods lines), Newport South Junction and Wodonga (branch lines), Dandenong, Drouin, Ferntree Gully, St Albans and Sydenham.

Re three position dwarf signals.

Low Speed Warning , Yellow light means the route is locked but the line ahead may be obstructed.
Clear Low Speed , Green light , next fixed signal at proceed, speed not to exceed 15 kph.

Dwarf light signals usually have only two lights where the lower light displays Red or Purple , and the Upper light Yellow.where a dwarf light signal could display a Green light this was ( at least until recently ) a miniature searchlight signal.until the closure of Melbourne Yard , this place was ( so I was told ) the only place that a Clear Low Speed signal could be observed. ( this may have recently changed ) .

For what it is worth, the last photo on this page refers:
http://www.victorianrailways.net/signaling/3posdw/3posdwar.html

This page may also be of interest:
http://www.victorianrailways.net/signaling/3pos02.html


Regards

Dear Gwiwer and others ,

British signalling practice is route based , both two position and Multi Aspect Signalling in the UK , and other railways that follow it , eg QR .

Route based signalling was two position semaphore in origin , when colour light signalling was first introduced in the UK in 1924 multiple signal light heads were used to display the route as was the practice for two position semaphore signalling. In some locations, especially where the Mainline was multi aspect , but the diverging line was two aspect , this practice continued and probably still holds true. ( I am open to correction on this last point. )

Where multi aspect junctions were concerned route indicators became the practice , either Route Indicator boxes showing a number/s or letter/s as appropriate, again an extension of two position signalling practice.
Or the use of feather route indicators , being a row of either 3 ( Southern Railway / Region , until 1966 ) or 5 lunar white lights at either 45 degree or 90 degree would be illuminated to indicate the diverging route only . Route indicator boxes were also used on post mounted dwarf signals controlling the entrance of trains into large yards.

Best wishes and regards, Radioman

Dear Gwiwer and others ,

VR ( and SAR ) three position signalling is speed based , not route based ( however see below ! ) . Hence the reason for the top arm or light being line speed , the middle arm or light being medium speed , and the lower arm or light being low speed.

On the VR the medium speed is normally used in the Inner Metropolitan Electrified Area to increase line capacity as the distance between signals is only sufficiently long to allow for braking capacity between the rear signal and the end of the train , which as a generalisation is about one and a half car length.

There is usually two signal protection between each train until the emergency brake signal overlap in front of a signal is cleared , ie train at location A, two signals behind train held at Red until train has moved past first rear signal's overlap , after which time second second in rear will change to a warning indication.

Therefore the line speed normally defines what signal indications you will receive . At Caulfield on the down departures from what is now platform 2 , in the Off Peak you will usually see Green over Red , Clear Normal Speed irrespective of whether you are set for either the Dandenong or the Frankston Line . These days there is also a top of post mounted LED theatre route indicator displaying either D or F as appropriate .

However , at some locations a Medium Speed indication will be recieved and it will be route based. Such signals are specified on the appropriate Signal Diagram .

Best wishes and regards, Radioman

Dear Kitchgp and others ,

Thank you Kitchgp for the photo links , they illustrate very well what I wrote .

Speed signalling is pre WW1 American in origin , and was originally intended to deal with the problem of mixing long heavy freight trains with the faster , shorter passenger trains on high density lines. It also allowed for track circuit ( another American invention ) operated automatic signalling which simultaneously increased line capacity and reduced costs by eliminating smaller Signal towers ( boxes ) .

Labour costs were significantly lower in the UK , such that automatic signalling and multi aspect signalling was quite uneconomic until post WW2 in the UK , hence the reason for the Mirfield ( LMS , Lancashire ) multi aspect ( and speed ) signalling scheme abolishing no signal boxes , as the additional cable runs were more expensive than retaining the signal boxes and associated staff. ( and the adjacent signal boxes were in view of each other . )

In the case of both Victoria and South Australia , speed signalling was upper quadrant with marker lights compared to two position signalling which was lower quadrant , therefore distinguishing between the two was not difficult.

Best wishes and regards, Radioman

Dear YM-Mundrabilla and others ,

You are correct YM that in antiquity disc and dwarf signals were normally ground based , however the VR seemed to favour post mounting of discs and dwarfs wherever possible and subject to other signal sighting issues . If you look at photos on Mark Bau's http://www.victorianrailways.net site , post mounting of discs and dwarfs is quite common , more so than other railways both in Australia and overseas .

I am a fan of British railways generally , and with the passage of time it became quite noticeable how often disc and dwarf signals that were ground based in the UK , when compared to a similar set up in Victoria, such a signal would be post mounted.

I therefore assume that the VR preferred to post mount where possible to ensure the driver had a clear view of the signal. The fact that the drivers at Epping Maintenance Depot were less than impressed with ground mounted dwarf signals would seem to reinforce that view . ( Over time I had spoken to many Epping based drivers , and others who frequented Epping , and it was a very common complaint. )

Best wishes and regards, Radioman

I was involved with the signal replacements at Epping in a past life.

It wasn't only the driver who disliked ground-mounted signals. Imagine the poor fitter crawling around on there ballast to maintain them. Raising the signals onto small posts (typically 1.2m high) made a world of difference to their comfort.

The re-wiring of the signals was due to them being upgraded to LED from incandescent, multi-lens types. Those signals were prone to mis-reading due to the sun shining directly into their lenses, falsely lighting up the yellow and washing out the red. Several drivers were caught out with that one. One drivers foreman was yelling at a driver one afternoon "Why isn't he going, he's got the stick" until I shaded the signal with a large piece of paper, at which point the yellow went out and the red lit up again. After that he was a fan of conversion also!

When disc signals were upgraded to 3-position signals, or replaced with LED sets, they often remained in their original position. At fRankston, we put in LED units on a signal bridge, so we had "dwarf" signals that were 40 feet tall!

In older locations where a signal was an after thought, many could not exceed a height of more than 24 inches(roughly) due to the clearance between the tracks.
An amendment appeared when the later colour light sub shunting signals were being introduced that the 'head' could be located on the ground or on a mast but the General Rules regarding Signals was to apply no matter where they were.

Hello All,

Re VR Three Position signalling . Normal Speed is defined as Line Speed for the Section, Medium Speed is a speed not exceeding 45 kph , except where  a 65 kph lilluminated light is also displayed. Low Speed is a speed not exceeding 15 kph .

Clear Normal Speed is Green over Red , next fixed signal is at proceed.
Normal Speed Warning is Yellow over Red , next fixed signal is at stop.
Stop is Red over Red.

Reduce to Medium Speed is Yellow over Green , next fixed signal displaying a Medium Speed Proceed Indication.

Clear Medium Speed is Red over Green , next fixed signal is at proceed.
Medium Speed Warning is Red over Yellow , next fixed signal is at stop.
Stop is Red over Red.

Best wishes and regards, Radioman.

Hello from North of the Border,

Here in NSW, the equivalent of VR "Reduce to Medium Speed" is Green over Yellow (2-light signalling in Sydney Metro area) or Flashing Yellow (Single-light signalling outside Metro area).
This can indicate (1) next signal at Caution (= VR Warning) OR (2) next signal at Medium for Turnout.
Question: In Vic locations where signals are closer than braking distance, does this require multiple Y/R warning  indications? (It seems to me that Y/G is only used where the next indication is R/Y or G but not for Y/R)

Ray

Yes you are correct a yellow over red is never preceded by yellow over green. That is not true in USA. If signals are close together the yellow over green is placed well out and then a sequence of red over green red over green red over yellow red over red will be used. At a number of locations now, a sequence yellow over green red over yellow red over red will step up to green over red yellow over red red over red when a full overlap is available. Of course the braking distance has to be adequate and the original sequence is due to a reduced overlap at the red over red.

Bill Johnston

Regarding clear low speed on a dwarf signal, my understanding is the section or block is clear but the next signal may be at stop.
Bill Johnston

Yes you are correct a yellow over red is never preceded by yellow over green. That is not true in USA. If signals are close together the yellow over green is placed well out and then a sequence of red over green red over green red over yellow red over red will be used. At a number of locations now, a sequence yellow over green red over yellow red over red will step up to green over red yellow over red red over red when a full overlap is available. Of course the braking distance has to be adequate and the original sequence is due to a reduced overlap at the red over red.

Bill Johnston

Thanks for reply, very interesting.
Here in Sydney there is an advanced medium, G/Flashing Y, usually on higher speed sections. The stop sequence is :  G/G - G/Flashing Y - G/Y - G/R - R/R/G (low speed) - R/R.  In earlier applications the G/Flashing Y is not used but the G/Y is shown on two consecutive signals where the spacing is close (e.g. City Underground and Harbour Bridge). The low speed signals are automatic and indicate line clear but no overlap at following stop signal. The train speed is controlled by lineside train stops.
Question: Are VR low-speed signals R/R/Y subject to track circuit clear to next signal?

Ray

Several questions to answer at once.

You must keep in mind that NSW signalling is unique to Australia, and probably the world. A form of route signalling, with strong basis on UK practise. Victorian practise for 3-position signalling is based on US practise, particularly the Pennsylvania Rail Road, and is referred to as "speed signalling".

A Clear Low Speed aspect (single green) is only found on Dwarf signals, and means the points are set for the move, the track is clear to the next signal, the next signal is showing some form of proceed aspect, maximum speed 15kmh. Where that Dwarf signal has the effect of admitting trains into a single line section (ATC or CTYC rules), then the green also allows the train to run at maximum speed after passing through all points applicable to that signal.

Modern application of speed signalling (basically since Laverton derailment about 40 years back) means that Vic applies an overlap beyond the stop aspect for the speed of a train approaching that signal. If a train can approach a signal at 160km/h, then the overlap has to be good for that speed. If there is only a short overlap, good for only 40km/h, then the stop aspect is approached by a Reduce To Medium Speed (Y/G, followed by a Medium Speed Warning (R/Y), to the stop.

That speed aspect is usually accompanied by some form of speed proving, so that if a train is failing to reduce speed it may get tripped (some form of intervention by the System forcing an emergency brake application). An example would be the train passes a Normal Speed Warning (Y/R), and when speed proven at a lower speed the next signal improves from STOP (R/R) to R/Y (or even R/G).

A "regrettable incident" at Epping Vic in 2002 was allowed to occur due to one driver becoming ill, passing one signal at full speed rather than 40km/h, then SPAD at the next; there was insufficient overlap too prevent the bingle, the overlap being only good for 40km/h, not 80. On the ATSB site if you want to read more.

Several questions to answer at once.

You must keep in mind that NSW signalling is unique to Australia, and probably the world. A form of route signalling, with strong basis on UK practise. Victorian practise for 3-position signalling is based on US practise, particularly the Pennsylvania Rail Road, and is referred to as "speed signalling".

A Clear Low Speed aspect (single green) is only found on Dwarf signals, and means the points are set for the move, the track is clear to the next signal, the next signal is showing some form of proceed aspect, maximum speed 15kmh. Where that Dwarf signal has the effect of admitting trains into a single line section (ATC or CTYC rules), then the green also allows the train to run at maximum speed after passing through all points applicable to that signal.

Modern application of speed signalling (basically since Laverton derailment about 40 years back) means that Vic applies an overlap beyond the stop aspect for the speed of a train approaching that signal. If a train can approach a signal at 160km/h, then the overlap has to be good for that speed. If there is only a short overlap, good for only 40km/h, then the stop aspect is approached by a Reduce To Medium Speed (Y/G, followed by a Medium Speed Warning (R/Y), to the stop.

That speed aspect is usually accompanied by some form of speed proving, so that if a train is failing to reduce speed it may get tripped (some form of intervention by the System forcing an emergency brake application). An example would be the train passes a Normal Speed Warning (Y/R), and when speed proven at a lower speed the next signal improves from STOP (R/R) to R/Y (or even R/G).

A "regrettable incident" at Epping Vic in 2002 was allowed to occur due to one driver becoming ill, passing one signal at full speed rather than 40km/h, then SPAD at the next; there was insufficient overlap too prevent the bingle, the overlap being only good for 40km/h, not 80. On the ATSB site if you want to read more.

1) Yes, the NSW system is somewhat idiosyncratic however it is fairly logical. In general, speeds are determined by speed boards and braking distances rather than signal indications except in Sydney Metro area where Caution (G/R) requires reduction to 50 km/h and for Low Speed (R/R/G) it is 30 km/h. Exceeding the required speed will result in emergency brake application initiated by lineside trip device.

2) Having lived in Canada and spent a lot of time working in USA I am familiar with North American practice. I might say that the VR system does not reflect Pennsylvania RR practice; they used position lights to replicate semaphore arm positions. I rode the PRR many times pre-Amtrak. The Victorian system appears to be a simplified version of the New York Central RR signal aspects.

3)  I take it that the VR Low Speed indication on a home post (R/R/Y) means points proven but the destination track may be occupied?

Ray

*snip*

3)  I take it that the VR Low Speed indication on a home post (R/R/Y) means points proven but the destination track may be occupied?

Ray

Correct, Route is set but the line ahead may be occupied. Proceed expecting to find the line ahead obstructed at a speed not exceeding 15kph.

Regarding clear low speed on a dwarf signal, my understanding is the section or block is clear but the next signal may be at stop.
Bill Johnston

Clear Low Speed = Route is set, line ahead is unoccupied, maximum speed 15kph, next fixed signal shows proceed.

2) Having lived in Canada and spent a lot of time working in USA I am familiar with North American practice. I might say that the VR system does not reflect Pennsylvania RR practice; they used position lights to replicate semaphore arm positions. I rode the PRR many times pre-Amtrak. The Victorian system appears to be a simplified version of the New York Central RR signal aspects.

The Pensylvania RR didn't always use position light signals. They were, in fact, first installed in 1915. The then signal engineer, A.H. Rudd, wanted to eliminate mechanisms on masts (which might freeze), avoid the 'colour' problem, and produce an extremely long range signal in fog.

Before that, the PRR had developed a speed signalling system using three position upper quadrant arms. In 1912 this was standardised by the (US) Railway Signal Association. This speed signalling system was what was adopted in 1915 by South Australia and Victoria. At the time this system was the world's best practice.

A more accurate description is that the former NYCRR used an elaboration of the 1912 RSA aspects. Most eastern US railroads elaborated the basic RSA aspects in the '20s as longer turnouts allowed higher diverging speeds than the basic 'medium speed'.

As an aside, the speed signalling system developed by the PRR was a very logical extension to the US standard practice in two position mechanical signalling. That's why it was accepted.

This speed signalling system was what was adopted in 1915 by South Australia and Victoria. At the time this system was the world's best practice.

1915 ?? USA style speed signalling was introduced in South Australia by commissioner W.A.Webb (1922 to 1930)

No.

Speed signalling was introduced into South Australia with the resignalling of Adelaide yard, the first stage of which was brought into service on 23 May 1915. The installation was supplied by GRS and cost (pounds) 23,000.

It was introduced by Charles G Pilkington, Assistant Engineer for Yards and Signals, under Joseph Moncrieff (Chief Engineer) and Alex Moncrieff (his brother and Commissioner). The Moncrieffs were conservative UK trained railway engineers, but were under sustained political pressure due to lack of initiative on the railways. Pilkington was a UK trained civil engineer who worked on the GWR. He joined the SAR in 1885 as a draftsman, and became Assistant Engineer for Signals and Interlocking in 1891. In 1923 he became Engineer for Signals and Telegraphs when Webb reorganised the administration of the railways.